Statics 1401- Final Exam-Chapters 1-11

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there are three ways to set up the null and alternative hypothese

1.Equal versus not equal hypothesis (two-tailed test) H0: parameter = some value H1: parameter ≠ some value 2.Equal versus less than (left-tailed test) H0: parameter = some value H1: parameter < some value 3.Equal versus greater than (right-tailed test)\ H0: parameter = some value H1: parameter > some value

A confidence interval was used to estimate the proportion of math majors that are female. A random sample of 72 math majors generated the following confidence interval: (0.438, 0.642). Using the information above, what size sample would be necessary if we wanted to estimate the true proportion to within 5% using 95% reliability? A) 382 B) 369 C) 400 D) 385

A controversial bill is being debated in the state legislature. Representative Williams wants to estimate within 2 percentage points and with 98% confidence the difference in the proportion of her male and female constituents who favor the bill. What sample size should she obtain? A) n1 = n2 = 6787 B) n1 = n2 = 4802 C) n1 = n2 = 136 D) n1 = n2 = 3394

A controversial bill is being debated in the state legislature. Representative Williams wants to estimate within 5 percentage points and with 95% confidence the difference in the proportion of her male and female constituents who favor the bill. What sample size should she obtain? A) n1 = n2 = 769 B) n1 = n2 = 542 C) n1 = n2 = 385 D) n1 = n2 = 39

A drug company wanted to test a new depression medication. The researchers found 400 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose depression symptoms decreased was recorded and compared. What type of experimental design is this? A) completely randomized design B) matched-pairs design C) single-blind design D) randomized block design

A farmer was interest in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 52 or fewer flights on average in the next 40 rows down which he drives his tractor? A) 0.0041 B) 0.9959 C) 0.0410 D) 0.4959

A farmer was interested in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 60 or more flights on average in the next 40 rows down which he drives his tractor? A) 0.0571 B) 0.5710 C) 0.4429 D) 0.9429

A lab orders a shipment of 100 rats a week, 52 weeks a year, from a rat supplier for experiments that the lab conducts. Prices for each weekly shipment of rats follow the distribution below: Price $10.00 $12.50 $15.00 Probability 0.4 0.25 0.35 How much should the lab budget for next year's rat orders assuming this distribution does not change. (Hint: find the expected price.) A) $643.50 B) $1238.00 C) $3,346,200.00 D) $12.38

A local eat-in pizza restaurant wants to investigate the possibility of starting to deliver pizzas. The owner of the store has determined that home delivery will be successful if the average time spent on the deliveries does not exceed 33 minutes. The owner has randomly selected 21 customers and has delivered pizzas to their homes in order to test if the mean delivery time actually exceeds 33 minutes. Suppose the P-value for the test was found to be 0.0270. State the correct conclusion. A) At α = 0.025, we fail to reject H0. B) At α = 0.02, we reject H0. C) At α = 0.03, we fail to reject H0. D) At α = 0.05, we fail to reject H0.

A manager wishes to determine the relationship between the number of miles traveled (in hundreds of miles) by her sales representatives and their amount of sales (in thousands of dollars) per month. Find the equation of the regression line for the given data. What would be the predicted sales if the sales representative traveled 0 miles? Is this reasonable? Why or why not? A) y ^ = 3.53x + 37.92; $37,920; No; it is not reasonable for a representative to travel 0 miles and have a positive amount of sales. B) y ^ = 37.92x + 3.53; $3792; Yes, it is reasonable. C) y ^ = 3.53x + 37.92; $3792; No; it is not reasonable for a representative to travel 0 miles and have a positive amount of sales. D) y ^ = 3.53x + 37.92; $37,920; Yes, it is reasonable

A national caterer determined that 87% of the people who sampled their food said that it was delicious. A random sample of 144 people is obtained from a population of 5000. The 144 people are asked to sample the caterer's food. Will the distribution of p ^ , the sample proportion saying that the food is delicious, be approximately normal? Answer Yes or No. A) Yes B) No

A nationwide survey claimed that at least 65% of parents with young children condone spanking their child as a regular form of punishment. In a random sample of 100 parents with young children, how many would need to say that they condone spanking as a form of punishment in order to refute the claim at α = 0.5? A) You would need 57 or less parents to support spanking to refute the claim. B) You would need more than 57 parents to support spanking to refute the claim. C) You would need 58 or less parents to support spanking to refute the claim. D) You would need exactly 57 parents to support spanking to refute the claim.

A pharmaceutical testing company wants to test a new cholesterol drug. The average cholesterol of the target population is 200 mg and they have a standard deviation of 25 mg. The company wished to test a sample of people who fall between 1.5 and 3 z-scores above the mean. Into what range must a candidate's cholesterol level be in order for the candidate to be included in the study? A) 237.5 - 275 B) 162.5 - 275 C) 225 - 237.5 D) 125 - 162.5

A random number generator is set to generate single digits between 0 and 9. One hundred and fifty random numbers are generated. The probability distribution for this random number generator is given below. What is the mean of this distribution? x 0 1 2 3 4 5 6 7 8 9 P(x) 0.09 0.12 0.11 0.08 0.09 0.13 0.10 0.07 0.10 0.11 A) 4.5 B) 7 C) 5 D) 6.6

A random variable is A) a numerical measure of the outcome of a probability experiment. B) generated by a random number table. C) the variable for which an algebraic equation is solved. D) a qualitative attribute of a population.

A severe drought affected several western states for 3 years. A Christmas tree farmer is worried about the drought's effect on the size of his trees. To decide whether the growth of the trees has been retarded, the farmer decides to take a sample of the heights of 25 trees and obtains the following results (recorded in inches): 60 57 62 69 46 54 64 60 59 58 75 51 49 67 65 44 58 55 48 62 63 73 52 55 50 Which measure of central tendency would be considered the best measure to use in this problem? A) mean B) mode C) range D) median

A single die is rolled twice. The set of 36 equally likely outcomes is {(1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6), (3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6), (4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6), (5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6), (6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)}. Find the probability of getting two numbers whose sum is greater than 9 and less than 13. A) 1/6 B) 5/36 C) 7/36 D) 0

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 460 with a standard deviation of 20 on a standardized test. Assuming a bell-shaped distribution, what percentage of scores exceeded 420? A) approximately 97.5% B) approximately 84% C) approximately 95% D) approximately 2.5%

A survey of 250 households showed 72 owned at least one snow blower. Find a point estimate for p, the population proportion of households that own at least one snow blower. A) 0.288 B) 0.224 C) 0.404 D) 0.712

An article a Florida newspaper reported on the topics that teenagers most want to discuss with their parents. The findings, the results of a poll, showed that 46% would like more discussion about the family's financial situation, 37% would like to talk about school, and 30% would like to talk about religion. These and other percentages were based on a national sampling of 539 teenagers. Estimate the proportion of all teenagers who want more family discussions about school. Use a 95% confidence level. Express the answer in the form p ^ ± E and round to the nearest thousandth. A) 0.37 ± 0.041 B) 0.63 ± 0.041 C) 0.37 ± 0.002 D) 0.63 ± 0.002

Based on 9500 responses from 29,000 questionnaires sent to all its members, a major medical association estimated that the annual salary of its members was $98,500 per year. What sampling technique was used? A) simple random B) convenience C) cluster D) systematic E) stratified

Calculate the linear correlation coefficient for the data below. A) -0.995 B) -0.671 C) -0.885 D) -0.778

Classify the following random variable: telephone area codes A) qualitative data B) quantitative discrete data C) experimental data D) quantitative continuous data

Compute the linear correlation coefficient between the two variables and determine whether a linear relation exists. x 2 3 5 5 6 y 1.3 1.6 2.1 2.2 2.7 A) r = 0.983; linear relation exists B) r = 0.883; linear relation exists C) r = 0.883; no linear relation exists D) r = 0.983; no linear relation exists

Computing the probability of the event "drawing a second red ball from a bag of colored balls after having kept the red ball that was drawn first from the bag" is an example of A) conditional probability. B) mutual exclusiveness. C) independence of events. D) disjoint events.

Construct a 95% confidence interval for p1 - p2 for a survey that finds 30% of 240 males and 41% of 200 females are opposed to the death penalty. A) (-0.200, -0.021) B) (-0.561, 0.651) C) (-1.324, 1.512) D) (-1.532, 1.342)

Describe the shape of the histogram. The data set: Pick-Three lottery results for 10 consecutive weeks 3 6 7 6 0 6 1 7 8 4 1 5 7 5 9 1 5 3 9 9 2 2 3 0 8 8 4 0 2 4 A) uniform B) symmetric C) skewed to the right D) skewed to the lef

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph cannot represent a normal density function because it increases as x becomes very large or very small. B) The graph cannot represent a normal density function because the area under the graph is greater than 1. C) The graph can represent a normal density function. D) The graph cannot represent a normal density function because it takes negative values for some values of

Fifty percent of the people that use the Internet order something online. Find the probability that only two of 9 Internet users will order something online. A) 0.070 B) 0.002 C) 9.000 D) 0.222

Find the probability that of 25 randomly selected housewives, no two share the same birthday. Round your answer to the nearest thousandth. A) 0.431 B) 0.068 C) 0.569 D) 0.995

Find the standardized test statistic t for a sample with n = 12, x = 19.5, s = 2.1, and α = 0.01 if H1: μ ≠ 20. Round your answer to three decimal places. A) -0.825 B) -0.381 C) -0.008 D) -0.037

Find the test statistic, t, to test the hypothesis that μ1 = μ2. Two samples are randomly selected and come from populations that are normal. The sample statistics are given below. n1 = 25 n2 = 30 x1 = 28 x2 = 26 s1 = 1.5 s2 = 1.9 A) 4.361 B) 1.986 C) 3.287 D) 2.892

Find the z-score for which the area under the standard normal curve to its left is 0.04. A) -1.75 B) -1.63 C) -1.48 D) -1.89

Find the z-score for which the area under the standard normal curve to its right is 0.70. A) -0.53 B) -0.47 C) -0.81 D) -0.98

For a standard normal curve, find the z-score that separates the bottom 30% from the top 70%. A) -0.53 B) -0.12 C) -0.47 D) -0.98

For a standard normal curve, find the z-score that separates the bottom 90% from the top 10%. A) 1.28 B) 2.81 C) 0.28 D) 1.52

Furnace repair bills are normally distributed with a mean of 269 dollars and a standard deviation of 20 dollars. If 64 of these repair bills are randomly selected, find the probability that they have a mean cost between 269 dollars and 271 dollars. A) 0.2881 B) 0.7881 C) 0.5517 D) 0.2119

Given the following five-number summary, find Q1. 2.9, 5.7, 10.0, 13.2, 21.1. A) 5.7 B) 10.0 C) 2.9 D) 13.2

Given the following least squares prediction equation, y^= -173 +74x, we estimate y to by with each 1-unit increase in x. A) increase; 74 B) decrease; 173 C) decrease; 74 D) increase; 173

H 0 : σ = 8.5 H 1 : σ < 8.5 A) Left-tailed, σ B) Right-tailed, μ C) Left-tailed, s D) Right-tailed, σ

If A, B, C, and D, are the only possible outcomes of an experiment, find the probability of D using the table below. Outcome A B C D Probability 1/14 1/14 1/14 . A) 1/4 B) 3/14 C) 1/14 D) 11/14

If X1, X2, X3, ..., XN are the N observations of a variable from a population, then the population mean is symbolized by A) μ B) Σ - C) X D) X

In a 1-pond bag of skittles the possible colors were red, green, yellow, orange, and purple. The probability ofdrawing a particular color from that bag is given below. Is this a probability model? A) Yes B) No

In a sandwich shop, the following probability distribution was obtained. The random variable x represents the number of condiments used for a hamburger. Find the mean and standard deviation for the random variable x. x P(x) 0 0.30 1 0.40 2 0.20 3 0.06 4 0.04 A) mean: 1.14; standard deviation: 1.04 B) mean: 1.30; standard deviation: 2.38 C) mean: 1.54; standard deviation: 1.30 D) mean: 1.30; standard deviation: 1.54

Is either histogram symmetric? A) Neither is symmetric. B) The first is symmetric, but the second is not symmetric. C) Both are symmetric. D) The second is symmetric, but the first is not symmetric.

One hundred people were asked, "Do you favor stronger laws on gun control?" Of the 33 that answered "yes" to the question, 14 were male. Of the 67 that answered "no" to the question, six were male. If one person is selected at random, what is the probability that this person answered "yes" or was a male? Round the the nearest hundredth. A) 0.39 B) 0.67 C) 0.53 D) 0.13

Quantitative variables classify individuals in a sample according to A) numerical measure. B) exhibited trait. C) physical attribute. D) personality characteristic.

Seven randomly selected plants that bottle the same beverage implemented a time management program in hopes of improving productivity. The average time, in minutes, that it took the companies to produce the same quantity of bottles before and after the program are listed below. Assume the two population distributions are normal. Construct a 90% confidence interval for μd. Assume that the paired data came from a population that is normally distributed. Plant 1 2 3 4 5 6 7 Before 75 89 31 90 120 50 40 After 70 80 30 85 100 49 42 A) (0.21, 10.93) B) (-0.22, 11.36) C) (1.60, 9.54) D) (-22, 33.3)

Smith is a weld inspector at a shipyard. He knows from keeping track of good and substandard welds that for the afternoon shift 5% of all welds done will be substandard. If Smith checks 300 of the 7500 welds completed that shift, what is the probability that he will find less than 20 substandard welds? A) 0.9066 B) 0.5934 C) 0.4066 D) 0.0934

Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.36 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains between 12.26 and 12.32 ounces. A) 0.1525 B) 0.8475 C) 0.8351 D) 0.1649

Telephone interviews of 318 employees of a large electronics company found that 45% were dissatisfied with their working conditions. A) statistic B) parameter

The average age of the 65 students in Ms. Hope's political science class is 21 years 6 months. A) parameter B) statistic

The data below are the average one-way commute times (in minutes) for selected students and the number of absences for those students during the term. Find the equation of the regression line for the given data. What would be the predicted number of absences if the commute time was 95 minutes? Is this a reasonable question? Round the predicted number of absences to the nearest whole number. Round the regression line values to the nearest hundredth. A) y ^ = 0.45x - 30.27; 12 absences; Yes, it is reasonable. B) y ^ = 0.45x + 30.27; 73 absences; No, it is not reasonable. 95 minutes is well outside the scope of the model. C) y ^ = 0.45x + 30.27; 73 absences; Yes, it is reasonable. D) y ^ = 0.45x - 30.27; 12 absences; No, it is not reasonable. 95 minutes is well outside the scope of the model.

The data set: ages of dishwashers (in years) in 20 randomly selected households 12 6 4 9 11 1 7 8 9 8 9 13 5 15 7 6 8 8 2 1 A) bell shaped B) skewed to the left C) skewed to the right D) uniform

The following data represents a random sample of 15 complaints registered with the customer service department of a store. Determine the median complaint. Other defective product excessive waiting time Messy store other other Messy store other messy store Other messy store messy store Defective product other messy store A) No median B) Excessive waiting time C) Messy store D) Defective product

The government of a town needs to determine if the city's residents will support the construction of a new town hall. The government decides to conduct a survey of a sample of the city's residents. Which one of the following procedures would be most appropriate for obtaining a sample of the town's residents? A) Survey a random sample of persons within each geographic region of the city. B) Survey every 7th person who walks into city hall on a given day. C) Survey the first 500 people listed in the town's telephone directory. D) Survey a random sample of employees at the old city hall.

The grade point averages for 10 randomly selected students in an algebra class with 125 students are listed below. What is the effect on the width of the confidence interval if the sample size is increased to 20? 2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 0.8 A) The width decreases. B) The width remains the same. C) The width increases. D) It is impossible to tell without more information.

The mean age of professors at a university is 58.4 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is not sufficient evidence to reject the claim μ = 58.4. B) There is not sufficient evidence to support the claim μ = 58.4. C) There is sufficient evidence to support the claim μ = 58.4. D) There is sufficient evidence to reject the claim μ = 58.4.

The overnight shipping business has skyrocketed in the last ten years. The single greatest predictor of a company's success has been proven time and again to be customer service. A study was conducted to study the customer satisfaction levels for one overnight shipping business. In addition to the customer's satisfaction level, the customers were asked how often they used overnight shipping. The results are shown below in the following table. A customer is chosen at random. Given that the customer uses the company two to five times per month, what is the probability that they expressed high satisfaction with the company? A) 7/10 B) 1/5 C) 7/23 D) 26/35

The personnel director at a large company would like to determine whether the company cafeteria is widely used by employees. She calls each employee and asks them whether they usually bring their own lunch, eat at the company cafeteria, or go out for lunch. A) observational study B) experiment

The policy committee at State University has 6 members: Dr. Hernandez, LaToyna, Ming, Jose, John, and Prof. Rise. A subcommittee of two members must be formed to investigate the visitation policy in the dormitories. List all possible simple random samples of size 2. A) Dr. Hernandez and LaToyna, Dr. Hernandez and Ming, Dr. Hernandez and Jose, Dr. Hernandez and John, Dr. Hernandez and Prof. Rise, LaToyna and Ming, LaToyna and Jose, LaToyna and John, LaToyna and Prof. Rise, Ming and Jose, Ming and John, Ming and Prof. Rise, Jose and John, Jose and Prof. Rise, John and Prof. Rise B) Dr. Hernandez and LaToyna, LaToyna and Ming, Ming and Jose, Jose and John, John and Prof. Rise C) Dr. Hernandez and LaToyna, Dr. Hernandez and Ming, Dr. Hernandez and Jose, Dr. Hernandez and John, Dr. Hernandez and Prof. Rise D) Dr. Hernandez and LaToyna, Ming and Jose, John and Prof. Rise

The produce manager at a farmer's market was interested in determining how many oranges a person buys when they buy oranges. He asked the cashiers over a weekend to count how many oranges a person bought when they bought oranges and record this number for analysis at a later time. The data is given below in the table. The random variable x represents the number of oranges purchased and P(x) represents the probability that a customer will buy x apples. Determine the mean number of oranges purchased by a customer A) 3.97 B) 5.50 C) 4 D) 3

The random variable x represents the number of girls in a family of three children. Assuming that boys and girls are equally likely, find the mean and standard deviation for the random variable x. A) mean: 1.50; standard deviation: 0.87 B) mean: 2.25; standard deviation: 0.76 C) mean: 2.25; standard deviation: 0.87 D) mean: 1.50; standard deviation: 0.76

The regression line for the given data is y = 4.379x + 4.267. Determine the residual of a data point for which x = 12.5 and y = 59. A) -0.0045 B) -250.128 C) 118.0045 D) 59.0045

The scores from a state standardized test have a bell-shaped distribution with a mean of 100 and a standard deviation of 15. Use the Empirical Rule to find the percentage of students with scores between 70 and 130. A) 95% B) 100% C) 99.7% D) 68%

The table below represents a random sample of the number of deaths per 100 cases for a certain illness over time. If a person infected with this illness is randomly selected from all infected people, find the probability that the person lives 3-4 years after diagnosis. Express your answer as a simplified fraction and as a decimal. A) 35/100 ; 0.35 B) 1 /35 ; 0.029 C) 7/ 120 ; 0.058 D) 35 /65 ; 0.538

The table lists the drinking habits of a group of college students. If a student is chosen at random, find the probability of getting someone who is a man or a woman. Round your answer to three decimal places. Sex Non-drinker Regular Drinker Heavy Drinker Total Man 135 59 5 199 Woman 187 21 14 222 Total 322 80 19 421 A) 1 B) 0.235 C) 0.765 D) 0.917

Two surgical procedures are widely used to treat a certain type of cancer. To compare the success rates of the two procedures, random samples of the two types of surgical patients were obtained and the numbers of patients who showed no recurrence of the disease after a 1-year period were recorded. The data are shown in the table. How large a sample would be necessary in order to estimate the difference in the true success rates to within 0.10 with 95% reliability? n Number of Successes Procedure A 100 95 Procedure B 100 97 A) n1 = n2 = 30 B) n1 = n2 = 20 C) n1 = n2 = 15 D) n1 = n2 = 192

What are the values of μx and σx for the sampling distribution of the sample mean shown? 390 440 490 A) μx = 440, σx = 50 B) μx = 50, σx = 440 C) μx = 440, σx = 100 D) μx = 440, σx = 150

When 460 junior college students were surveyed,100 said that they have previously owned a motorcycle. Find a point estimate for p, the population proportion of students who have previously owned a motorcycle. A) 0.217 B) 0.278 C) 0.783 D) 0.179

When the results of a hypothesis test are determined to be statistically significant, then we _______________ the null hypothesis. A) reject B) polarize C) fail to reject D) compartmentalize

Which measure of central tendency is more representative of the typical observation if the graph of the data is skewed to the right? A) Median B) Mean C) Midrange D) Mode

the native languages of students in an English class A) qualitative B) quantitative

the number of calls received at a company's help desk A) quantitative B) qualitative

the temperature in degrees Celsius on January 1st in Fargo, North Dakota A) continuous B) discrete

the weight of a player on the wrestling team A) continuous B) discrete

A bag contains 25 wooden beads. The colors of the beads are red, blue, white, green, black, brown, and grey. The probability of randomly selecting a bead of a particular color from the bag is given below. Is this a probability model? Answer yes or No. A) Yes B) No

A medical journal published the results of an experiment on anorexia. The experiment investigated the effects of a controversial new therapy for anorexia. Researchers measured the anorexia levels of 84 adult women who suffer moderate conditions of the disorder. After the therapy, the researchers again measured the women's anorexia levels. The differences between the the pre- and post-therapy anorexia levels were reported. What type of experimental design is this? A) completely randomized design B) matched-pairs design C) randomized block design D) single-blind design

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 460 seconds and a standard deviation of 40 seconds. Find the probability that a randomly selected boy in secondary school can run the mile in less than 368 seconds. A) 0.4893 B) 0.0107 C) 0.5107 D) 0.9893

A simple random sample of size n < 30 has been obtained. From the boxplot, judge whether a t-interval should be constructed. A) No; the data are normally distributed, but there are outliers B) No, though there are no outliers, the data are not normally distributed but right skewed C) No, there are outliers and the data are not normally distributed but right skewed D) Yes; the data are normally distributed and there are no outliers

A small computing center has found that the number of jobs submitted per day to its computers has a distribution that is approximately bell shaped, with a mean of 76 jobs and a standard deviation of 7. Where do we expect most (approximately 95%) of the distribution to fall? A) between 62 and 97 jobs per day B) between 62 and 90 jobs per day C) between 55 and 97 jobs per day D) between 69 and 83 jobs per day

A study of 3100 college students in the city of Pemblington found that 4% had been victims of violent crimes. A) parameter B) statistic

A survey claims that 9 out of 10 doctors (i.e., 90%) recommend brand Z for their patients who have children. To test this claim against the alternative that the actual proportion of doctors who recommend brand Z is less than 90%, a random sample of doctors was taken. Suppose the test statistic is z = -2.23. Can we conclude that H0 should be rejected at the a) α =0.10, b) α = 0.05, and c) α = 0.01 level? A) a) no; b) no; c) no B) a) yes; b) yes; c) no C) a) yes; b) yes; c) yes D) a) no; b) no; c) yes

A travel industry researcher interviews all of the passengers on five randomly selected cruises. What sampling technique is used? A) convenience B) cluster C) systematic D) stratified E) simple random

A writer for an art magazine randomly selects and interviews fifty male and fifty female artists. What sampling technique is used? A) convenience B) stratified C) simple random D) cluster E) systematic

According to a study conducted in one city, 36% of adults in the city have credit card debts of more than $2000. A simple random sample of n = 150 adults is obtained from the city. Describe the sampling distribution of p^ the sample proportion of adults who have credit card debts of more than $2000. A) Binomial; μp = 54, σp = 5.88 B) Approximately normal; μp = 0.36, σp = 0.039 C) Exactly normal; μp = 0.36, σp = 0.039 D) Approximately normal; μp = 0.36, σp = 0.0015

According to the Federal Communications Commission, 70% of all U.S. households have vcrs. In a random sample of 15 households, what is the probability that the number of households with vcrs is between 10 and 12, inclusive? A) 0.4053 B) 0.5947 C) 0.7 D) 0.2061

According to the law of large numbers, as more observations are added to the sample, the difference between the sample mean and the population mean A) Tends to become larger B) Tends to become smaller C) Is inversely affected by the data added D) Remains about the same

An instructor wishes to determine if there is a relationship between the number of absences from his class and a student's final grade in the course. What is the explanatory variable? A) The instructor's point scale for attendance B) Absences C) Student's performance on the final examination D) Final Grade

Assume that the heights of men are normally distributed with a mean of 66.9 inches and a standard deviation of 2.1 inches. If 36 men are randomly selected, find the probability that they have a mean height greater than 67.9 inches. A) 0.9005 B) 0.0021 C) 0.9979 D) 0.0210

At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve speed of a particular player was 103 miles per hour (mph) and the standard deviation of the serve speeds was 14 mph. Assume that the statistician also gave us the information that the distribution of the serve speeds was bell shaped. What proportion of the player's serves are expected to be between 131 mph and 145 mph? A) 0.95 B) 0.0235 C) 0.047 D) 0.997

Compute the linear correlation coefficient between the two variables and determine whether a linear relation exists x 5 7 14 11 9 8 10 12 13 6 y -11 -9 8 0 -3 -7 -2 2 5 -9 A) r = 0.819; linear relation exists B) r = 0.990; linear relation exists C) r = 0.881; no linear relation exists D) r = 0.792; no linear relation exists

Construct a 90% confidence interval for the population mean, μ. Assume the population has a normal distribution. In a recent study of 22 eighth graders, the mean number of hours per week that they played video games was 19.6 with a standard deviation of 5.8 hours. Round to the nearest hundredth. A) (19.62, 23.12) B) (17.47, 21.73) C) (5.87, 7.98) D) (18.63, 20.89)

Construct a 95% confidence interval for the population mean, μ. Assume the population has a normal distribution. A random sample of 16 lithium batteries has a mean life of 645 hours with a standard deviation of 31 hours. Round to the nearest tenth. A) (321.7, 365.8) B) (628.5, 661.5) C) (531.2, 612.9) D) (876.2, 981.5)

Construct a 95% confidence interval for μ1 - μ2. Two samples are randomly selected from each population. The sample statistics are given below. n1 = 50 n2 = 60 x1 = 25 x2 = 23 s1 = 1.5 s2 = 1.9 A) (1.919, 3.142) B) (1.364, 2.636) C) (1.572, 2.987) D) (1.723, 3.012)

Eleven high school teachers were asked to give the number of students in their classes. The sample data follows. Would any of the class sizes be considered an outlier? Answer Yes or No. 36, 31, 30, 31, 20, 19, 24, 34, 21, 28, 24 A) Yes B) No

Find the area under the standard normal curve to the left of z = 1.25. A) 0.2318 B) 0.8944 C) 0.7682 D) 0.1056

Find the class width for the frequency table below. Class Frequency 22-23 3 24-25 1 26-27 3 28-29 6 30-31 2 A) 1 B) 2 C) 1.5 D) 2.5

Find the critical value for a left-tailed test with α = 0.025. A) -2.575 B) -1.96 C) -2.24 D) -1.645

Find the standardized test statistic t for a sample with n = 12, x = 19.2, s = 2.2, and α = 0.01 if H0: μ = 18. Round your answer to three decimal places. A) 2.132 B) 1.890 C) 1.991 D) 2.001

Find the standardized test statistic t for a sample with n = 25, x = 26, s = 3, and α = 0.005 if H1: μ > 25. Round your answer to three decimal places. A) 1.997 B) 1.667 C) 1.452 D) 1.239

Find the z-score for which the area under the standard normal curve to its left is 0.09. A) -1.45 B) -1.34 C) -1.26 D) -1.39

For a standard normal curve, find the z-score that separates the bottom 70% from the top 30%. A) 0.98 B) 0.53 C) 0.47 D) 0.12

Given the following five-number summary, find the IQR. 2.9, 5.7, 10.0, 13.2, 21.1. A) 18.2 B) 7.5 C) 11.1 D) 7.1

Suppose you want to test the claim that μ > 25.6. Given a sample size of n = 58 and a level of significance of α = 0.05, when should you reject H0? A) Reject H0 if the standardized test statistic is greater than 1.28. B) Reject H0 if the standardized test statistic is greater than 1.645. C) Reject H0 if the standardized test statistic is greater than 2.575. D) Reject H0 if the standardized test statistic is greater than 2.33.

The amount of corn chips dispensed into a 19-ounce bag by the dispensing machine has been identified as possessing a normal distribution with a mean of 19.5 ounces and a standard deviation of 0.2 ounce. Suppose 400 bags of chips were randomly selected from this dispensing machine. Find the probability that the sample mean weight of these 400 bags exceeded 19.6 ounces. A) 0.3085 B) approximately 0 C) 0.1915 D) 0.6915

The city council of a small town needs to determine if the town's residents will support the building of a new library. The council decides to conduct a survey of a sample of the town's residents. Which one of the following procedures would be most appropriate for obtaining a sample of the town's residents? A) Survey 300 individuals who are randomly selected from a list of all people living in the state in which the town is located. B) Survey a random sample of persons within each neighborhood of the town. C) Survey every 13th person who enters the old library on a given day. D) Survey a random sample of librarians who live in the town

The data below are ages and systolic blood pressures (measured in millimeters of mercury) of 9 randomly selected adults. Find the equation of the regression line for the given data. What would be the predicted pressure if the age was 60? Round the predicted pressure to the nearest whole number. Round the regression line values to the nearest hundredth. A) y ^ = 60.46x - 1.49; 3626 mm B) y ^ = 1.49x + 60.46; 150 mm C) y ^ = 1.49x - 60.46; 29 mm D) y ^ = 60.46x + 1.49; 3629 mm

The data below are the final exam scores of 10 randomly selected chemistry students and the number of hours they slept the night before the exam. What is the best predicted value for y given x = 5? A) 80 B) 81 C) 79 D) 82

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they slept the night before the exam. Compute the sum of the squared residuals of the least-squares line for the given data. A) 1122.1 B) 318.038 C) 39.755 D) 804.062

The graph of a normal curve is given. Use the graph to identify the value of μ and σ A) μ = 6, σ = -6 B) μ = -6, σ = 2 C) μ = 2, σ = -6 D) μ = -6, σ = 6

The mean number of rushing yards for one NFL team was less than 96 yards per game. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is sufficient evidence to reject the claim μ < 96. B) There is not sufficient evidence to support the claim μ < 96. C) There is sufficient evidence to support the claim μ < 96. D) There is not sufficient evidence to reject the claim μ < 96

The number of violent crimes committed in a day possesses a distribution with a mean of 3.5 crimes per day and a standard deviation of 4 crimes per day. A random sample of 100 days was observed, and the mean number of crimes for the sample was calculated. Describe the sampling distribution of the sample mean. A) approximately normal with mean = 3.5 and standard deviation = 4 B) approximately normal with mean = 3.5 and standard deviation = 0.4 C) shape unknown with mean = 3.5 and standard deviation = 0.4 D) shape unknown with mean = 3.5 and standard deviation = 4

The object upon which the response variable is measured is called ________ . A) the factor B) an experimental unit C) a treatment D) the predictor variable

The peak shopping time at a pet store is between 8-11:00 am on Saturday mornings. Management at the pet store randomly selected 95 customers last Saturday morning and decided to observe their shopping habits. They recorded the number of items that a sample of the customers purchased as well as the total time the customers spent in the store. Identify the types of variables recorded by the pet store. A) number of items - continuous; total time - continuous B) number of items - discrete; total time - continuous C) number of items - discrete; total time - discrete D) number of items - continuous; total time - discrete

The probability that a house in an urban area will develop a leak is 6%. If 24 houses are randomly selected, what is the probability that none of the houses will develop a leak? A) 0.003 B) 0.227 C) 0.060 D) 0.000

The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1200 miles. What is the probability a certain tire of this brand will last between 57,480 miles and 57,840 miles? A) 0.4649 B) 0.0180 C) 0.9813 D) 0.4920

Which of the following is not a characteristic of Students' t-distribution? A) depends on degrees of freedom. B) mean of 1 C) symmetric distribution D) For large samples, the t and z distributions are nearly equivalent.

With which model was the greatest percentage satisfied? Estimate the empirical probability that a person with this model is very satisfied with the experience. Express the answer as a fraction with a denominator of 100 A) Model F; 57/100 B) Model A; 81/100 C) Model A: 0.81/100 D) Model F; 0.57/100

an officer's rank in the military A) interval B) ordinal C) ratio D) nominal

the age of the oldest dog in a kennel A) discrete B) continuous

A candidate for state representative of a certain state claims to be favored by at least half of the voters. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is not sufficient evidence to reject the claim p ≥ 0.5. B) There is sufficient evidence to support the claim p ≥ 0.5. C) There is sufficient evidence to reject the claim p ≥ 0.5. D) There is not sufficient evidence to support the claim p ≥ 0.5.

A farmer wishes to test the effects of a new fertilizer on her soybean yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four C's are treated with no fertilizer. At harvest time, the soybean yield is recorded for each section of land. What is the response variable in this experiment? A) the type of fertilizer (old, new, or none) B) the section of land (A, B, or C) C) the soybean yield recorded for each section of land D) the four types of soil

A game has three outcomes. The probability of a win is 0.4, the probability of tie is 0.5, and the probability of a loss is 0.1. What is the probability of not winning in a single play of the game. A) 0.33 B) 0.1 C) 0.6 D) 0.5

A greenhouse in a tri-county area has kept track of its customers for the last several years and has determined that 28% of its customers plant a vegetable garden in the spring. The greenhouse obtains a random sample of 1000 of its customers. What is the mean of the sampling distribution of p ^ , the sample proportion of customers that plant a vegetable garden in the spring? A) 0.72 B) 2800 C) 0.28 D) 0.002

A group of wine tasters rated Chardonnay wines from two different wineries as poor, acceptable, good or excellent. A) quantitative, dependent B) quantitative, independent C) qualitative, dependent D) qualitative, independent

A local bank needs information concerning the savings account balances of its customers. A random sample of 15 accounts was checked. The mean balance was $686.75 with a standard deviation of $256.20. Find a 98% confidence interval for the true mean. Assume that the account balances are normally distributed. Round to the nearest cent. A) ($487.31, $563.80) B) ($326.21, $437.90) C) ($513.17, $860.33) D) ($238.23, $326.41)

A local country club has a membership of 600 and operates facilities that include an 18-hole championship golf course and 12 tennis courts. Before deciding whether to accept new members, the club president would like to know how many members regularly use each facility. A survey of the membership indicates that 69% regularly use the golf course, 41% regularly use the tennis courts, and 4% use neither of these facilities regularly. Given that a randomly selected member uses the tennis courts regularly, find the probability that they also use the golf course regularly. A) 0.146 B) 0.203 C) 0.341 D) 0.127

A local tennis pro-shop strings tennis rackets at the tension (pounds per square inch) requested by the customer. Recently a customer made a claim that the pro-shop consistently strings rackets at lower tensions, on average, than requested. To support this claim, the customer asked the pro shop to string 20 new rackets at 56 psi. Upon receiving the rackets, the customer measured the tension of each and calculated the following summary statistics: x = 52 psi, s = 2.7 psi. In order to conduct the test, the customer selected a significance level of α = .05. Interpret this value. A) The smallest value of α that you can use and still reject H0 is 0.05. B) The probability of making a Type II error is 0.95. C) The probability of concluding that the true mean is less than 56 psi when in fact it is equal to 56 psi is only .05. D) There is a 5% chance that the sample will be biased.

A manufacturer of cellular phones has decided that an assembly line is operating satisfactorily if less than 0.03% of the phones produced per day are defective. To check the quality of a day's production, the company decides to randomly sample 10 phones from a day's production to test for defects. Define the population of interest to the manufacturer. A) the 10 phones sampled and tested B) the 0.03% of the phones that are defective C) all the phones produced during the day in question D) the 10 responses: defective or not defective

A medical journal published the results of an experiment on anxiety. The experiment investigated the effects of a controversial new therapy for anxiety. Researchers measured the anxiety levels of 31 adult women who suffer moderate conditions of the disorder. After the therapy, the researchers again measured the women's anxiety levels. The differences between the the pre- and post-therapy anxiety levels were reported. What is the response variable in this experiment? A) the therapy B) the 31 adult women who suffer from anxiety C) the differences between the the pre- and post-therapy anxiety levels D) the disorder (anxiety or no anxiety)

A medical journal published the results of an experiment on insomnia. The experiment investigated the effects of a controversial new therapy for insomnia. Researchers measured the insomnia levels of 33 adult women who suffer moderate conditions of the disorder. After the therapy, the researchers again measured the women's insomnia levels. The differences between the the pre- and post-therapy insomnia levels were reported. What is the treatment in this experiment? A) the 33 adult women who suffer from insomnia B) the disorder (insomnia or no insomnia) C) the therapy D) the differences between the the pre- and post-therapy insomnia levels

A probability experiment is conducted in which the sample space of the experiment is S = {5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}. Let event A = {8, 9, 10, 11, 12}. Assume that each outcome is equally likely. List the outcomes in Ac. Find P(Ac). A) {13, 14, 15}; 3/11 B) {5, 6, 7, 12, 13, 14, 15}; 7/11 C) {5, 6, 7, 13, 14, 15}; 6/11 D) {8, 9, 10, 11, 12}; 5/11

A recent survey found that 73% of all adults over 50 wear sunglasses for driving. In a random sample of 20 adults over 50, what is the mean and standard deviation of those that wear sunglasses? A) mean: 5.4; standard deviation: 1.98544705 B) mean: 5.4; standard deviation: 3.82099463 C) mean: 14.6; standard deviation: 1.98544705 D) mean: 14.6; standard deviation: 3.82099463

A relative frequency histogram for the sale prices of homes sold in one city during 2010 is shown below. Based on the histogram, is a large sample necessary to conduct a hypothesis test about the mean sale price? If so, why? A) No; data appear to be normally distributed. B) Yes; data do not appear to be normally distributed but skewed left. C) Yes; data do not appear to be normally distributed but skewed right. D) Yes; data do not appear to be normally distributed but bimodal.

A researcher randomly selected 100 adults aged 18-25 and 100 adults aged 50-60. Within each age group, she recorded the number of smokers. A) quantitative, dependent B) qualitative, dependent C) qualitative, independent D) quantitative, independent

A researcher wishes to estimate the number of households with two computers. How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the true proportion by more than 2%? A previous study indicates that the proportion of households with two computers is 18%. A) 5 B) 2984 C) 2447 D) 2004

A simple random sample of size n < 30 has been obtained. From the boxplot, judge whether a t-interval should be constructed. A) No, there are no outliers but the data are not normally distributed B) No, there are outliers and the data are not normally distributed C) No; the data appear roughly normally distributed but there are outliers D) Yes; the data appear normally distributed and there are no outliers

A simple random sample of size n < 30 has been obtained. From the boxplot, judge whether a t-interval should be constructed. A) No; there are no outliers, but the data are not normally distributed B) No; the data appear roughly normally distributed, but there are outliers C) Yes; the data appear roughly normally distributed and there are no outliers D) No; the data are not normally distributed and there are outliers

A study was conducted to determine if the salaries of librarians from two neighboring cities were equal. A sample of 15 librarians from each city was randomly selected. The mean from the first city was $28,900 with a standard deviation of $2300. The mean from the second city was $30,300 with a standard deviation of $2100. Construct a 95% confidence interval for μ1 - μ2. A) (-2871, 567) B) (-2054, 238) C) (-3125, 325) D) (-4081, 597)

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 340 with a standard deviation of 50 on a standardized test. Assuming a bell-shaped distribution, where would approximately 95% of the students score? A) below 190 or above 490 B) below 240 or above 440 C) between 240 and 440 D) between 190 and 490

According to government data, the probability that an adult was never in a museum is 15%. In a random survey of 10 adults, what is the probability that at least eight were in a museum? A) 0.800 B) 0.200 C) 0.820 D) 0.002

At a local technical school, five auto repair classes are randomly selected and all of the students from each class are interviewed. What sampling technique is used? A) systematic B) stratified C) cluster D) convenience E) simple random

Classify the statement as an example of classical probability, empirical probability, or subjective probability. The probability that it will snow tomorrow is 84%. A) empirical probability B) classical probability C) subjective probability

Classify the statement as an example of classical probability, empirical probability, or subjective probability. In one state lottery, a person selects a 4-digit number. The probability of winning this state's lottery is 1 10,000 . A) empirical probability B) subjective probability C) classical probability

Construct a 90% confidence interval for the population mean, μ. Assume the population has a normal distribution. A sample of 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation of 0.78. Round to the nearest hundredth. A) (2.41, 3.42) B) (2.28, 3.66) C) (2.51, 3.21) D) (2.37, 3.56)

Construct a 95% confidence interval for the population mean, μ. Assume the population has a normal distribution. A sample of 20 part-time workers had mean annual earnings of $3120 with a standard deviation of $677. Round to the nearest dollar. A) ($1324, $1567) B) ($2135, $2567) C) ($2803, $3437) D) ($2657, $2891)

Construct a 95% confidence interval for μ1 - μ2. Two samples are randomly selected from each population. The sample statistics are given below. n1 = 40 n2 = 35 x1 = 12 x2 = 13 s1 = 2.5 s2 = 2.8 A) (-1.673, 1.892) B) (-2.001, -1.873) C) (-2.209, 0.209) D) (-1.968, 1.561)

Describe the shape of the histogram. The data set: age of 20 household stereo systems randomly selected from a neighborhood 12 6 4 9 11 1 7 8 9 8 9 13 5 15 7 6 8 8 2 1 A) skewed to the right B) skewed to the left C) symmetric D) uniform

Determine the critical value for a right-tailed test of a population mean at the α = 0.025 level of significance with 19 degrees of freedom. A) 2.101 B) -2.093 C) 2.093 D) 3.174

Determine the standardized test statistic, z, to test the claim about the population proportion p > 0.015 given n = 150 and p^= 0.027. Use α = 0.01. A) 1.56 B) 1.06 C) 1.21 D) 3.14

Determine the two z-scores that separate the middle 87.4% of the distribution from the area in the tails of the standard normal distribution. A) -1.45, 1.45 B) -1.39, 1.39 C) -1.53, 1.53 D) -1.46, 1.46

Each year advertisers spend billions of dollars purchasing commercial time on network sports television. In the first 6 months of 1988, advertisers spent $1.1 billion. A recent article listed the top 10 leading spenders (in millions of dollars): Company A $70 Company F $26.3 Company B 61.3 Company G 26.1 Company C 57.5 Company H 22.5 Company D 56.3 Company I 22.1 Company E 28.7 Company J 19.7 Calculate the mean amount spent. A) 384.88 million dollars B) 19.62 million dollars C) 39.05 million dollars D) 50.30 million dollars

Each year advertisers spend billions of dollars purchasing commercial time on network sports television. In the first 6 months of the year, advertisers spent $1.1 billion. A recent article listed the top 10 leading spenders (in millions of dollars): Company A $72.8 Company F $27.1 Company B 60.7 Company G 27 Company C 57.9 Company H 23.7 Company D 54.7 Company I 23.4 Company E 31.1 Company J 20.9 Calculate the median. A) 5.39 million dollars B) 51.90 million dollars C) 29.10 million dollars D) 39.93 million dollars

Find the area under the standard normal curve between z = -1.25 and z = 1.25. A) 0.6412 B) 0.2112 C) 0.7888 D) 0.8817

Find the population mean or sample mean as indicated. Sample: 5, 8, 13, 17, 22 A) μ = 12 B) μ = 13 C)-x = 13 D) -x = 14

Find the t-value such that the area left of the t-value is 0.2 with 4 degrees of freedom. A) -2.999 B) 0.978 C) -0.941 D) 0.941

Find the test statistic to test the hypothesis that μ1 = μ2. Two samples are randomly selected from each population. The sample statistics are given below. Use α = 0.05. n1 = 50 n2 = 60 x1 = 33 x2 = 31 s1 = 1.5 s2 = 1.9 A) 3.8 B) 4.2 C) 6.2 D) 8.1

Find the test statistic to test the hypothesis that μ1 ≠ μ2. Two samples are randomly selected from each population. The sample statistics are given below. Use α = 0.02. n1 = 51 n2 = 38 x1 = 2.6 x2 = 3 s1 = 0.76 s2 = 0.51 A) -2.32 B) -1.82 C) -2.97 D) -2.12

H 0 : p = 0.94 H 1 : p > 0.94 A) Right-tailed, p ^ B) Left-tailed, p C) Right-tailed, p D) Left-tailed, p^

Suppose a population has a mean of 7 for some characteristic of interest and a standard deviation of 9.6. A sample is drawn from this population of size 64. What is the standard error of the mean? A) 0.7 B) 0.15 C) 1.2 D) 3.3

The boxplot shown below was constructed in Excel for the amount of soda that was poured by a filling machine into 12-ounce soda cans at a local bottling company. Based on the information given in the boxplot below, what shape do you believe the data to have? A) skewed to the right B) approximately symmetric C) skewed to the left D) cannot be determined

The business college computing center wants to determine the proportion of business students who have personal computers (PC's) at home. If the proportion exceeds 25%, then the lab will scale back a proposed enlargement of its facilities. Suppose 200 business students were randomly sampled and 65 have PC's at home. What assumptions are necessary for this test to be satisfied? A) The sample variance equals the population variance. B) The population has an approximately normal distribution. C) No assumptions are necessary. D) The sample mean equals the population mean.

The data below are the average one-way commute times (in minutes) for selected students and the number of absences for those students during the term. Find the equation of the regression line for the given data. What would be the predicted number of absences if the commute time was 40 minutes? Is this a reasonable question? Round the predicted number of absences to the nearest whole number. Round the regression line values to the nearest hundredth. A) y= 0.45x - 30.27; -12 absences; Yes, it is reasonable. B) y= 0.45x + 30.27; 48 absences; Yes, it is reasonable. C) y= 0.45x - 30.27; -12 absences; No, it is not reasonable. 40 minutes is well outside the scope of the model. D) y= 0.45x + 30.27; 48 absences; No, it is not reasonable. 40 minutes is well outside the scope of the model.

The dean of a major university claims that the mean number of hours students study at her University (per day) is at most 3.4 hours. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is sufficient evidence to reject the claim μ ≤ 3.4. B) There is sufficient evidence to support the claim μ ≤ 3.4. C) There is not sufficient evidence to reject the claim μ ≤ 3.4. D) There is not sufficient evidence to support the claim μ ≤ 3.4.

The distribution of Bachelor's degrees conferred by a university is listed in the table. Assume that a student majors in only one subject. What is the probability that a randomly selected student with a Bachelor's degree majored in Physics or Philosophy? Round your answer to three decimal places. Major Frequency Physics 228 Philosophy 208 Engineering 86 Business 176 Chemistry 222 A) 0.526 B) 0.226 C) 0.474 D) 0.248

The events A and B are mutually exclusive. If P(A) = 0.7 and P(B) = 0.1, what is P(A or B)? A) 0.6 B) 0 C) 0.8 D) 0.07

The following data are the yields, in bushels, of hay from a farmer's last 10 years: 375, 210, 150, 147, 429, 189, 320, 580, 407, 180. Find the IQR. A) 265 B) 279 C) 227 D) 253

The following data represent the living situation of newlyweds in a large metropolitan area and their annual household income. What percent of people who live with family make between $35,000 and $50,000 per year? Round to the nearest tenth of a percent A) 2.1% B) 35.6% C) 15.5% D) 10.6%

The grade point averages for 10 randomly selected junior college students are listed below. Assume the grade point averages are normally distributed. Find a 98% confidence interval for the true mean. Round to the nearest hundredth. 2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 0.8 A) (2.12, 3.14) B) (0.67, 1.81) C) (1.55, 3.53) D) (3.11, 4.35)

The heights of ten female students (in inches) in a college math class are listed below. Find the mean. 65 66 67 66 67 70 67 70 71 68 A) 65.5 inches B) 71.1 inches C) 67.7 inches D) 70.0 inches

The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 7.0 minutes and a standard deviation of 1 minute. Find the cut-off time which 75.8% of the college students exceed when trying to find a parking spot in the library parking lot. A) 7.8 min B) 7.5 min C) 7.7 min D) 7.3 min

The manager of a used car lot took inventory of the automobiles on his lot and constructed the following table based on the age of his car and its make (foreign or domestic). A car was randomly selected from the lot. Given that the car selected was a foreign car, what is the probability that it was older than 2 years? Age of Car (in years) A) 42/113 B) 58/113 C) 29/50 D) 21/50

The manager of a used car lot took inventory of the automobiles on his lot and constructed the following table based on the age of his car and its make (foreign or domestic). A car was randomly selected from the lot. Given that the car selected was a domestic car, what is the probability that it was older than 2 years? A) 21/50 B) 10/21 C) 3/5 D) 1 /5

The mean number of rushing yards for one NFL team was less than 98 yards per game. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is not sufficient evidence to support the claim μ < 98. B) There is not sufficient evidence to reject the claim μ < 98. C) There is sufficient evidence to support the claim μ < 98. D) There is sufficient evidence to reject the claim μ < 98.

The owner of a computer repair shop has determined that their daily revenue has mean $7200 and standard deviation $1200. The daily revenue totals for the next 30 days will be monitored. What is the probability that the mean daily revenue for the next 30 days will exceed $7500? A) 0.0869 B) 0.9131 C) 0.0853 D) 0.9147

The principal at Riverside High School would like to estimate the mean length of time each day that it takes all the buses to arrive and unload the students. How large a sample is needed if the principal would like to assert with 90% confidence that the sample mean is off by, at most, 7 minutes. Assume that s = 14 minutes based on previous studies. A) 13 B) 12 C) 11 D) 10

The regression line for the given data is y ^ = -0.206x + 2.097. Determine the residual of a data point for which x = 4 and y = 8. A) 1.273 B) 3.551 C)6.727 D) 9.273

The sum of the probabilities of a discrete probability distribution must be A) greater than one. B) less than or equal to zero. C) equal to one. D) between zero and one

To help consumers assess the risks they are taking, the Food and Drug Administration (FDA) publishes the amount of nicotine found in all commercial brands of cigarettes. A new cigarette has recently been marketed. The FDA tests on this cigarette gave a mean nicotine content of 28.5 milligrams and standard deviation of 2.8 milligrams for a sample of n = 9 cigarettes. The FDA claims that the mean nicotine content exceeds 31.7 milligrams for this brand of cigarette, and their stated reliability is 95%. Do you agree? A) No, since the value 31.7 does fall in the 95% confidence interval. B) Yes, since the value 31.7 does fall in the 95% confidence interval. C) No, since the value 31.7 does not fall in the 95% confidence interval. D) Yes, since the value 31.7 does not fall in the 95% confidence interval.

Two surgical procedures are widely used to treat a certain type of cancer. To compare the success rates of the two procedures, random samples of the two types of surgical patients were obtained and the numbers of patients who showed no recurrence of the disease after a 1-year period were recorded. The data are shown in the table. How large a sample would be necessary in order to estimate the difference in the true success rates to within 0.10 with 95% reliability? n Number of Successes Procedure A 100 91 Procedure B 100 83 A) n1 = n2 = 43 B) n1 = n2 = 192 C) n1 = n2 = 86 D) n1 = n2 = 60

Use the linear correlation coefficient given to determine the coefficient of determination, R2. r = -0.28 A) R2 = 52.92% B) R2 = -7.84% C) R2 = 7.84% D) R2 = -52.92%

What effect will an outlier have on a confidence interval that is based on a small sample size? A) The interval will be smaller than an interval without the outlier. B) The interval will reveal exclusionary data. C) The confidence interval will be wider than an interval without the outlier. D) The interval will be the same with or without the outlier.

What is the difference between a bar chart and a histogram? A) There is no difference between these two graphical displays. B) The bars in a bar chart are all the same width while the bars of a histogram may be of various widths. C) The bars on a bar chart do not touch while the bars of a histogram do touch. D) The bars in a bar chart may be of various widths while the bars of a histogram are all the same width.

he data below are the average one-way commute times (in minutes) for selected students and the number of absences for those students during the term. Find the equation of the regression line for the given data. What would be the predicted number of absences if the commute time was 40 minutes? Is this a reasonable question? Round the predicted number of absences to the nearest whole number. Round the regression line values to the nearest hundredth. A) y= 0.45x - 30.27; -12 absences; Yes, it is reasonable. B) y= 0.45x + 30.27; 48 absences; Yes, it is reasonable. C) y= 0.45x - 30.27; -12 absences; No, it is not reasonable. 40 minutes is well outside the scope of the model. D) y= 0.45x + 30.27; 48 absences; No, it is not reasonable. 40 minutes is well outside the scope of the model.

x 9 2 3 4 2 5 9 10 y 85 52 55 68 67 86 83 73 A) r = 0.708; no linear relation exists B) r = -0.708; linear relation exists C) r = 0.708; linear relation exists D) r = 0.235; no linear relation exists

A researcher wanted to determine whether women with children are more likely to develop anxiety disorders than women without children. She selected a sample of 900 twenty-year old women and followed them for a twenty-year period. At the start of the study, none of the women had children. By the end of the study 53% of the women had at least one child. The level of anxiety of each participant was evaluated at the beginning and at the end of the study and the increase (or decrease) in anxiety was recorded. The researchers analyzed the results to determine whether there was an association between anxiety and having children. A) retrospective; Individuals are asked to look back in time. B) cross-sectional; Information is collected at a specific point in time. C) cohort; Individuals are observed over a long period of time.

C) cohort; Individuals are observed over a long period of time.

Researchers wanted to determine whether there was an association between high blood pressure and the suppression of emotions. The researchers looked at 1800 adults enrolled in a Health Initiative Observational Study. Each person was interviewed and asked about their response to emotions. In particular they were asked whether their tendency was to express or to hold in anger and other emotions. The degree of suppression of emotions was rated on a scale of 1 to 10. Each person's blood pressure was also measured. The researchers analyzed the results to determine whether there was an association between high blood pressure and the suppression of emotions. A) cohort; Individuals are observed over a long period of time. B) retrospective; Individuals are asked to look back in time. C) cross-sectional; Information is collected at a specific point in time.

C) cross-sectional; Information is collected at a specific point in time.

Guidelines for Determining the Lower Class Limit of the First Class and Class Width

ClassW= largest data value- smallest data value -------------------------------------------- number of classes Round this value up to a convenient numbe

A new phone system was installed last year to help reduce the expense of personal calls that were being made by employees. Before the new system was installed, the amount being spent on personal calls followed a normal distribution with an average of $700 per month and a standard deviation of $50 per month. Refer to such expenses as PCE's (personal call expenses). Using the distribution above, what is the probability that a randomly selected month had a PCE of between $575.00 and $790.00? A) 0.0421 B) 0.9999 C) 0.0001 D) 0.9579

A new phone system was installed last year to help reduce the expense of personal calls that were being made by employees. Before the new system was installed, the amount being spent on personal calls follows a normal distribution with an average of $700 per month and a standard deviation of $50 per month. Refer to such expenses as PCE's (personal call expenses). Find the probability that a randomly selected month had a PCE that falls below $550. A) 0.2143 B) 0.9987 C) 0.7857 D) 0.0013

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 450 seconds and a standard deviation of 50 seconds. Find the probability that a randomly selected boy in secondary school will take longer than 335 seconds to run the mile. A) 0.0107 B) 0.5107 C) 0.4893 D) 0.9893

A salesman boasts to a farmer that his new fertilizer will increase the yield of the farmer's crops by 15%. The farmer wishes to test the effects of the new fertilizer on her corn yield. She has four equal sized plots of land one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal sized portions and randomly labels them A, B and C. The four A portions are treated with her old fertilizer. The four B portions are treated with the new fertilizer. The four C portions receive no fertilizer. At harvest time, the corn yield is recorded for each section of land. What is the claim she is testing? A) The average soil field had at least a 15% increase in yield. B) The A sections had at least a 15% increase in yield. C) The total yield increased at least 15%. D) The new fertilizer yielded at least a 15% improvement.

A sample consists of every 20th worker from a group of 5000 workers. What sampling technique was used? A) stratified B) simple random C) cluster D) systematic E) convenience

A seed company has a test plot in which it is testing the germination of a hybrid seed. They plant 50 rows of 40 seeds per row. After a two-week period, the researchers count how many seed per row have sprouted. They noted that least number of seeds to germinate was 33 and some rows had all 40 germinate. The germination data is given below in the table. The random variable x represents the number of seed in a row that germinated and P(x) represents the probability of selecting a row with that number of seed germinating. Determine the mean number of seeds per row that germinated A) 36 B) 36.5 C) 0.13 D) 36.9

A severe drought affected several western states for 3 years. A Christmas tree farmer is worried about the drought's effect on the size of his trees. To decide whether the growth of the trees has been retarded, the farmer decides to take a sample of the heights of 25 trees. Typically trees of this age have a mean height of 65 inches with a standard deviation of 9 inches. Assuming the distribution is bell shaped, where do you expect middle 95% of the tree heights to fall? A) over 56 inches tall B) between 38 and 92 inches tall C) between 56 and 74 inches tall D) between 47 and 83 inches tall

A survey of 1010 college seniors working towards an undergraduate degree was conducted. Each student was asked, "Are you planning or not planning to pursue a graduate degree?" Of the 1010 surveyed, 658 stated that they were planning to pursue a graduate degree. Construct and interpret a 98% confidence interval for the proportion of college seniors who are planning to pursue a graduate degree. A) (0.612, 0.690); we are 98% confident that the proportion of college seniors who are planning to pursue a graduate degree is between 0.612 and 0.690. B) (0.620, 0.682); we are 98% confident that the proportion of college seniors who are planning to pursue a graduate degree is between 0.620 and 0.682. C) (0.621, 0.680); we are 98% confident that the proportion of college seniors who are planning to pursue a graduate degree is between 0.621 and 0.680. D) (0.616, 0.686); we are 98% confident that the proportion of college seniors who are planning to pursue a graduate degree is between 0.616 and 0.686.

An education researcher randomly selects 30 of the nation's junior colleges and interviews all of the professors at each school. What sampling technique was used? A) systematic B) stratified C) simple random D) cluster E) convenience

Assume that male and female births are equally likely and that the birth of any child does not affect the probability of the gender of any other children. Find the probability of at most three girls in ten births. A) 0.333 B) 0.003 C) 0.300 D) 0.172

Compare a graph of the normal density function with mean of 0 and standard deviation of 1 with a graph of a normal density function with mean equal to 4 and standard deviation of 1. The graphs would A) Have the same height but one would be shifter 4 units to the left. B) Have no horizontal displacement but one would be flatter than the other. C) Have no horizontal displacement but one would be steeper that the other. D) Have the same height but one would be shifted 4 units to the right.

Consider the data in the table shown which represents the marital status of males and females 18 years or older in the United States in 2003. Determine the probability that a randomly selected U.S. resident 18 years or older is divorced or a male? Round to the nearest hundredth. A) 0.58 B) 0.04 C) 0.50 D) 0.54

Construct a 95% confidence interval for the population mean, μ. Assume the population has a normal distribution. A sample of 25 randomly English majors has a mean test score of 81.5 with a standard deviation of 10.2. Round to the nearest hundredth. A) (66.35, 69.89) B) (87.12, 98.32) C) (56.12, 78.34) D) (77.29, 85.71)

Construct a 95% confidence interval for μ1 - μ2. Two samples are randomly selected from normal populations. The sample statistics are given below. n1 = 11 n2 = 18 x1 = 4.8 x2 = 5.2 s1 = 0.76 s2 = 0.51 A) (-4.152, 3.981) B) (-1.762, 1.762) C) (-2.762, 2.762) D) (-0.977, 0.177)

Construct a 99% confidence interval for the population mean, μ. Assume the population has a normal distribution. A group of 19 randomly selected employees has a mean age of 22.4 years with a standard deviation of 3.8 years. Round to the nearest tenth. A) (16.3, 26.9) B) (18.7, 24.1) C) (17.2, 23.6) D) (19.9, 24.9)

Describe the shape of the histogram. The data set: round-trip commuting times (in minutes) of 20 randomly selected employees 135 120 115 132 136 124 119 145 98 110 125 120 115 130 140 105 116 121 125 108 A) symmetric B) skewed to the left C) uniform D) skewed to the right

Determine the area under the standard normal curve that lies between: z = 1 and z = 2 A) 0.0008 B) 0.8641 C) 0.0006 D) 0.1359

Determine the critical value zα/2 that corresponds to the given level of confidence. 94% A) 1.61 B) 1.555 C) 0.83 D) 1.88

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph can represent a normal density function. B) The graph cannot represent a normal density function because a normal density curve should approach but not reach the horizontal axis as x increases and decreases without bound. C) The graph cannot represent a normal density function because it is bimodal. D) A and B are both true

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph cannot represent a normal density function because the area under the graph is less than 1. B) The graph cannot represent a normal density function because its maximum value is too small. C) The graph cannot represent a normal density function because it has no inflection points. D) The graph can represent a normal density function

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph cannot represent a normal density function because as x increases without bound, the graph takes negative values. B) The graph cannot represent a normal density function because the area under the graph is greater than 1. C) The graph cannot represent a normal density function because it has no inflection points. D) The graph can represent a normal density function.

Fifteen randomly selected men were asked to run on a treadmill for 6 minutes. After the 6 minutes, their pulses were measured and the following data were obtained: 105 94 98 88 104 101 99 85 84 124 122 114 97 101 90 A) (95.2, 105.6); we are 95% confident that the mean pulse rate of men after 6 minutes of exercise is between 95.2 and 105.6 beats per minute. B) (94.2, 106.6); we are 95% confident that the mean pulse rate of men after 6 minutes of exercise is between 94.2 and 106.6 beats per minute. C) (94.9, 105.9); we are 95% confident that the mean pulse rate of men after 6 minutes of exercise is between 94.9 and 105.9 beats per minute. D) (93.7, 107.1); we are 95% confident that the mean pulse rate of men after 6 minutes of exercise is between 93.7 and 107.1 beats per minute.

Find the critical t-value that corresponds to 95% confidence and n = 16. A) 1.753 B) 2.947 C) 2.602 D) 2.131

Find the equation of the regression line for the given data. Round values to the nearest thousandth. A) y ^ = 0.522x - 2.097 B) y ^ = 2.097x + 0.552 C) y ^ = -0.552x + 2.097 D) y ^ = 2.097x - 0.552

Find the standardized test statistic t for a sample with n = 10, x = 9.6, s = 1.3, and α = 0.05 if H0: μ ≥ 10.5. Round your answer to three decimal places. A) -3.186 B) -3.010 C) -2.617 D) -2.189

Find the test statistic to test the hypothesis that μ1 < μ2. Two samples are randomly selected from each population. The sample statistics are given below. Use α = 0.05. n1 = 35 n2 = 42 x1 = 25.02 x2 = 27.57 s1 = 2.9 s2 = 2.8 A) -3.16 B) -1.66 C) -2.63 D) -3.90

Find the z-score for the value 66, when the mean is 51 and the standard deviation is 1. A) z = 14.00 B) z = 1.27 C) z = -1.27 D) z = 15.00

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of senior citizens whose net worth is too high to qualify for government health care but who have no private health insurance. The ages of 25 uninsured senior citizens were as follows: 72 77 70 80 90 78 65 93 69 94 73 96 80 66 85 67 72 85 74 77 64 91 79 68 86 Find Q1 of the data. A) 70 B) 69 C) 77.5 D) 69.5

How much money does the average professional hockey fan spend on food at a single hockey game? That question was posed to 10 randomly selected hockey fans. The sampled results show that sample mean and standard deviation were $16.00 and $2.6, respectively. Use this information to create a 90% confidence interval for the mean. Express the answer in the form x ± tα/2(s/ n). A) 16 ± 1.383(2.6/ 10) ' B) 16 ± 1.796(2.6/ 10) C) 16 ± 1.812(2.6/ 10) D) 16 ± 1.833(2.6/ 10)

In an area of the Great Plains, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). Compute the sum of the squared residuals of the least-squares line for the given data. Rain fall (in inches), A) 2207.628 B) 4.379 C) 0 D) 87.192

In the game of roulette in the United States a wheel has 38 slots: 18 slots are black, 18 slots are red, and 2 slots are green. The P(Red) = 18 38 ≈ 0.47. This is an example of what type of probability? A) Simulated B) Subjective C) Empirical D) Classical

John has six bills of paper money in the following denominations: $1, $5, $10, $20, $50, and $100 If he selects 3 bills at a time how many, how many groups can be formed? A) 30 B) 15 C) 10 D) 20

Let t0 be a specific value of t. Find t0 such that the statement is true: P(t ≤ t0) = 0.05 where df = 20. A) 1.729 B) 1.725 C) -1.729 D) -1.725

Many firms use on-the-job training to teach their employees new software. Suppose you work in the personnel department of a firm that just finished training a group of its employees in new software, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean and standard deviation of the test scores are 84 and 4, respectively, and the distribution of scores is bell shaped. What percentage of test-takers scored better than a trainee who scored 72? A) approximately 95% B) approximately 97.5% C) approximately 84% D) approximately 99.85%

Many people think that a national lobby's successful fight against gun control legislation is reflecting the will of a minority of Americans. A previous random sample of 4000 citizens yielded 2250 who are in favor of gun control legislation. How many citizens would need to be sampled if a 99% confidence interval was desired to estimate the true proportion to within 5%? A) 664 B) 690 C) 611 D) 653

One hundred men suffering from high cholesterol were randomly assigned to receive placebo or a cholesterol-lowering medication. After three months, the mean cholesterol level of those receiving placebo was compared with the mean cholesterol level of those receiving the medication. A) qualitative, dependent B) quantitative, dependent C) qualitative, independent D) quantitative, independent

Parking at a large university has become a very big problem. University administrators are interested in determining the average parking time (e.g. the time it takes a student to find a parking spot) of its students. An administrator inconspicuously followed 300 students and carefully recorded their parking times. Identify the population of interest to the university administration. A) the students that park at the university between 9 and 10 AM on Wednesdays B) the parking times of the 300 students from whom the data were collected C) the entire set of faculty, staff, and students that park at the university D) the parking times of the entire set of students that park at the university

Recently, the stock market took big swings up and down. A survey of 993 adult investors asked how often they tracked their portfolio. The table shows the investor responses. What is the probability that an adult investor tracks his or her portfolio daily? Express your answer as a simplified fraction and as a decimal rounded to three decimal places. A) 298/993 ; 0.3 B) 272/993 ; 0.274 C) 133/993 ; 0.134 D) 236/993 ; 0.238

Sixty-five percent of men consider themselves knowledgeable soccer fans. If 12 men are randomly selected, find the probability that exactly four of them will consider themselves knowledgeable fans. A) 0.333 B) 0.65 C) 0.237 D) 0.020

Solar energy is considered by many to be the energy of the future. A recent survey was taken to compare the cost of solar energy to the cost of gas or electric energy. Results of the survey revealed that the distribution of the amount of the monthly utility bill of a 3-bedroom house using gas or electric energy had a mean of $99 and a standard deviation of $9. If the distribution can be considered bell shaped, what percentage of homes will have a monthly utility bill of more than $90? A) approximately 32% B) approximately 16% C) approximately 95% D) approximately 84%

Suppose a 90% confidence interval for μ turns out to be (1000, 2100). If this interval was based on a sample of size n = 22, explain what assumptions are necessary for this interval to be valid. A) The sampling distribution of the sample mean must have a normal distribution. B) The population of salaries must have an approximate t distribution. C) The sampling distribution must be biased with 21 degrees of freedom. D) The population must have an approximately normal distribution.

Suppose that E and F are two events and that P(E and F) = 0.32 and P(E) = 0.8. What is P(F/E)? A) 0.256 B) 1.12 C) 2.5 D) 0.4

Suppose you want to test the claim that μ < 65.4. Given a sample size of n = 35 and a level of significance of α = 0.05, when should you reject H0? A) Reject H0 if the standardized test statistic is less than -1.28. B) Reject H0 if the standardized test is less than -2.575. C) Reject H0 if the standardized test statistic is less than -2.33. D) Reject H0 if the standardized test statistic is less than -1.645.

The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered investment properties. If a sample of 800 homes sold in 2004 is obtained what is the probability that between 175 and 200 homes are going to be used as investment property? A) 0.7764 B) 0.9099 C) 0.2236 D) 0.1335

The ages of five randomly chosen cars in a parking garage are determined to be 7, 9, 3, 4, and 6 years old. If we consider this sample of 5 in groups of 3, how many groups can be formed? A) 60 B) 30 C) 5 D) 10

The amount of corn chips dispensed into a 32-ounce bag by the dispensing machine has been identified as possessing a normal distribution with a mean of 32.5 ounces and a standard deviation of 0.2 ounce. What chip amount represents the 67th percentile for the bag weight distribution? Round to the nearest hundredth. A) 32.09 oz B) 32.63 oz C) 32.13 oz D) 32.59 oz

The below table shows the probabilities generated by rolling one die 50 times and noting the up face. What is the probability of getting an odd up face and a two or less? Round the the nearest hundredth. Roll 1 2 3 4 5 6 Probability 0.22 0.10 0.18 0.12 0.18 0.20 A) 0.66 B) 0.32 C) 0.90 D) 0.68

The commuting times (in minutes) of an employee for ten consecutive days are listed below. Find the median commute. 71 67 67 72 76 72 73 68 72 72 A) 71 minutes B) 67 minutes C) 73 minutes D) 72 minutes

The conditional probability of event G, given the knowledge that event H has occurred, would be written as . A) P(H|G) B) P(G) C) P(H) D) P(G|H)

The data below are the ages and annual pharmacy b ills (in dollars) of 9 randomly selected employees. Calculate the linear correlation coefficient. A) 0.998 B) 0.890 C) 0.908 D) 0.960

The data below are the average one-way commute times (in minutes) of selected students during a summer literature class and the number of absences for those students for the term. Calculate the linear correlation coefficient. A) 0.890 B) 0.819 C) 0.881 D) 0.980

The data below are the final exam scores of 10 randomly selected calculus students and the number of hours they slept the night before the exam. Calculate the linear correlation coefficient. A) 0.761 B) 0.654 C) 0.991 D) 0.847

The data set: Pick Three Lottery Outcomes for 10 Consecutive Weeks 3 6 7 6 0 6 1 7 8 4 1 5 7 5 9 1 5 3 9 9 2 2 3 0 8 8 4 0 2 4 A) bell shaped B) skewed to the left C) skewed to the right D) uniform

The median of a data set for a variable is the data value that A) Appears the most often B) Is the average, that is, the sum of all the data values of the variable divided by the number of observations in the data set? C) None of these D) Lies in the middle of the data when the data is arranged in ascending order.

The one way distances from work (in miles) of 30 employees are listed below. Find Q2. 25 25 26 26.5 27 27 27.5 28 28 28.5 29 29 30 30 30.5 31 31 32 32.5 32.5 33 33 34 34.5 35 35 37 37 38 38 A) 31.75 mi B) 34 mi C) 28 mi D) 30.75 mi

The owner of a computer repair shop has determined that their daily revenue has mean $7200 and standard deviation $1200. The daily revenue totals for the next 30 days will be monitored. What is the probability that the mean daily revenue for the next 30 days will be less than $7000? A) 0.8186 B) 0.5675 C) 0.4325 D) 0.1814

The random variable x represents the number of tests that a patient entering a clinic will have along with the corresponding probabilities. Find the mean and standard deviation for the random variable x. A) mean: 1.59; standard deviation: 3.72 B) mean: 2.52; standard deviation: 1.93 C) mean: 3.72; standard deviation: 2.52 D) mean: 1.59; standard deviation: 1.09

The sample space for tossing three fair coins is {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}. What is the probability of exactly two heads? A) 5/8 B) 3 C) 1/2 D) 3/8

The scores from a state standardized test have a mean of 80 and a standard deviation of 10. The distribution of the scores is roughly bell shaped. Use the Empirical Rule to find the percentage of scores that lie between 60 and 80. A) 68% B) 95% C) 34% D) 47.5%

The variable measured in the experiment is called ____________ . A) the predictor variable B) a sampling unit C) the treatment D) the response variable

To avoid working late, the plant foreman inspects the first 20 microwaves produced that day. What sampling technique was used? A) stratified B) systematic C) cluster D) convenience E) simple random

Two samples are said to be dependent if A) some individuals, but not all, in one sample exert influence over who is selected for inclusion in a second ample. B) sampling for inclusion in the two samples is done with replacement. C) the individuals in one sample have no influence over the selection of the individuals in a second sample. D) the individuals in one sample are used to determine the individuals in a second sample.

We never conclude "Accept H0" in a test of hypothesis. This is because: A) α is the probability of a Type I error. B) The p-value is not small enough. C) The rejection region is not known. D) β = p(Type II error) is not known.

he table below summarizes the weights of the almonds (in grams) in a one-pound bag. What is the class width? Weight (g) Frequency 0.7585 -0.8184 1 0.8185 -0.8784 1 0.8785 -0.9384 1 0.9385 -0.9984 3 0.9985 -1.0584 157 1.0585 -1.1184 171 1.1185 -1.1784 8 A) 0.4 B) 0.408 C) 0.059 D) 0.06

the graph of a distribution of data shows that the graph is symmetric then the A) Median is a better measure of central tendency B) Mode is a better measure of central tendency C) Midrange is a better measure of central tendency D) Mean is a better measure of central tendency

the medal received (gold, silver, bronze) by an Olympic gymnast A) interval B) ratio C) nominal D) ordinal

A marketing research company needs to estimate which of two medical plans its employees prefer. A random sample of n employees produced the following 98% confidence interval for the proportion of employees who prefer plan A: (0.308, 0.588). Identify the point estimate for estimating the true proportion of employees who prefer that plan. A) 0.308 B) 0.588 C) 0.14 D) 0.448

D) To Find, (1-0.98)= 0.02 0.588/0.02=29.4 0.308/0.02=15.4 29.4+15.4=44.8/100=0.448

A random number generator is set top generate integer random numbers between 1 and 10 inclusive following a uniform distribution. What is the probability of the random number generator generating a 7? A) 0 B) 0.07 C) 0.5 D) 0.7

D) To Find: 1-7 ----=0.667=0.7 1-10

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 460 seconds and a standard deviation of 60 seconds. The fitness association wants to recognize the boys whose times are among the top (or fastest) 10% with certificates of recognition. What time would the boys need to beat in order to earn a certificate of recognition from the fitness association? A) 361.3 sec B) 536.8 sec C) 558.7 sec D) 383.2 sec

D) To Find: 2nd, vars, int -->left zscore x sd + mean

The relative frequency is the proportion (or percent) of observations within a category and is found using the formula

RF= F/sum of all frequencies

Parallel Example 2: Forming Hypotheses For each of the following claims, determine the null and alternative hypotheses. State whether the test is two-tailed, left-tailed or right-tailed. a)In 2008, 62% of American adults regularly volunteered their time for charity work. A researcher believes that this percentage is different today b)According to a study published in March, 2006 the mean length of a phone call on a cellular telephone was 3.25 minutes. A researcher believes that the mean length of a call has increased since then. c)Using an old manufacturing process, the standard deviation of the amount of wine put in a bottle was 0.23 ounces. With new equipment, the quality control manager believes the standard deviation has decreased

a.The hypothesis deals with a population proportion, p. If the percentage participating in charity work is no different than in 2008, it will be 0.62 so the null hypothesis is H0: p = 0.62. Since the researcher believes that the percentage is different today, the alternative hypothesis is a two-tailed hypothesis: H1: p≠ 0.62. b.The hypothesis deals with a population mean, μ. If the mean call length on a cellular phone is no different than in 2006, it will be 3.25 minutes so the null hypothesis is H0: μ=3.25. Since the researcher believes that the mean call length has increased, the alternative hypothesis is:H1: μ> 3.25, a right-tailed test c.The hypothesis deals with a population standard deviation, σ. If the standard deviation with the new equipment has not changed, it will be 0.23 ounces so the null hypothesis is H0: σ= 0.23. Since the quality control manager believes that the standard deviation has decreased, the alternative hypothesis is: H1: σ< 0.23, a left-tailed test

Determine whether the quantitative variables are discrete or continuous. (a) The number of heads obtained after flipping a coin five times. (b) The number of cars that arrive at a McDonald's drive-thru between 12:00 p.m. and 1:00 p.m. (c) The distance a 2014 Toyota Prius can travel in city driving conditions with a full tank of gas.

a.discrete b.discrete c. continuous (measurable, miles, ft, inches,grams)

For each of the following variables, determine the level of measurement. (a) Gender (b) Temperature (c) Number of days during the past week that a college student studied (d) Letter grade earned in your statistics class

a.nominal b.interval c.ratio d.ordinal

A hypothesis is a statement regarding a characteristic of

one or more populations. In this chapter, we look at hypotheses regarding a single population parameter

A matched-pairs design is an experimental design in which the experimental units are

paired up. The pairs are matched up so that they are somehow related (that is, the same person before and after a treatment, twins, husband and wife, same geographical location, and so on). There are only two levels of treatment in a matched-pairs design

An international relations professor is supervising four master's students. Information about the students is summarized in the table. Student Name Student Number Area of Interest GPA Anna 914589205 Africa 3.73 Pierre 981672635 Middle East 3.31 Juan 906539012 Latin America 3.34 Yoko 977530271 Asia 3.80 Identify the variables and determine whether each variable is quantitative or qualitative. A) student number: quantitative; area of interest: qualitative; GPA: qualitative B) student number: quantitative; area of interest: qualitative; GPA: quantitative C) student number: qualitative; area of interest: qualitative; GPA: quantitative D) student number: qualitative; area of interest: qualitative; GPA: qualitative

The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 6.5 minutes and a standard deviation of 1 minute. Find the probability that a randomly selected college student will take between 5.0 and 7.5 minutes to find a parking spot in the library lot. A) 0.4938 B) 0.2255 C) 0.7745 D) 0.0919

The sampling distribution of the sample mean is shown. If the sample size is n = 36, what is the standard deviation of the population from which the sample was drawn? Round to the nearest thousandth where appropriate. 290 330 370 A) σ = 6.667 B) σ = 1440 C) σ = 240 D) σ = 1.111

The standard error of the mean is given by A) μ - x B) μ - x C) σ/n D) μ ± σ

Rules of probabilities

1. The probability of any event E, P(E), must be greater than or equal to 0 and less than or equal to 12. The sum of the probabilities of all outcomes must equal 1

Every fifth adult entering an airport is checked for extra security screening. What sampling technique is used? A) systematic B) cluster C) convenience D) stratified E) simple random

A quiz consists of 20 true or false questions. If the student guesses on each question, what is the standard deviation of the number of correct answers? A) 3.16227766 B) 2.23606798 C) 0 D) 2

Find the population mean or sample mean as indicated. Population: 6, 10, 2, 11, 14, 5 A) μ = 11 B) μ = 8 C) -x = 9 D) -x = 10

SAS was used to compare the high school dropout rates for the 30 school districts in one city in 2010 and 2012. The box plots generated for these dropout rates are shown below. Compare the center of the distributions and the variation of the distributions for the two years. YEAR 2010 2012 A) Dropout rates had a lower average with more variability in 2010 than in 2012. B) Dropout rates had a higher average with less variability in 2010 than in 2012. C) Dropout rates had a higher average with more variability in 2010 than in 2012. D) Dropout rates had a lower average with less variability in 2010 than in 2012.

High temperatures in a certain city for the month of August follow a uniform distribution over the interval 66°F to 88°F. What is the probability that a randomly selected August day has a high temperature that exceeded 71°F? A) 0.0455 B) 0.7727 C) 0.461 D) 0.2273

B) P= 88-71 ------- =0.7727 88-66

A die is rolled. The set of equally likely outcomes is {1, 2, 3, 4, 5, 6}. Find the probability of getting a 3. A) 1/2 B) 0 C) 3 D) 1/6

A senator wishes to estimate the proportion of United States voters who favor abolishing the Electoral College. How large a sample is needed in order to be 90% confident that the sample proportion will not differ from the true proportion by more than 5%? A) 164 B) 542 C) 9 D) 271

A survey of 700 non-fatal accidents showed that 183 involved faulty equipment. Find a point estimate for p, the population proportion of accidents that involved faulty equipment. A) 0.739 B) 0.207 C) 0.354 D) 0.261

Consider the discrete probability distribution to the right when answering the following question. Find the probability that x equals 4. x 2 4 6 9 P(x) 0.12 ? 0.15 0.03 A) 1.2 B) 0.3 C) 2.8 D) 0.7

Describe the sampling distribution of p ^ N = 24,000, n = 450, p = 0.7 A) Binomial; μp = 315, σp = 9.72 B) Approximately normal; μp = 0.7, σp = 0.0935 C) Exactly normal; μp = 0.7, σp = 0.022 D) Approximately normal; μp = 0.7, σp = 0.022

Determine the area under the standard normal curve that lies between: z = -0.3 and z = 0.3 A) 0.5 B) 0.3821 C) 0.6179 D) 0.2358

Find the critical t-value that corresponds to 99% confidence and n = 10. A) 2.262 B) 1.833 C) 2.821 D) 3.250

Find the sum of the areas under the standard normal curve to the left of z = -1.25 and to the right of z 1.25 A) 0.3944 B) 0.7888 C) 0.1056 D) 0.2112

Suppose x is a uniform random variable with c = 20 and d = 50. Find the probability that a randomly selected observation exceeds 32. A) 0.9 B) 0.4 C) 0.1 D) 0.6

The level of significance, α, is the probability of making a A) Type β error B) Correct decision C) Type II error D) Type I error

The regression line for the given data is y ^ = 6.91x + 46.26. Determine the residual of a data point for which x = 7 and y = 93 A) 94.63 B) 187.63 C) -681.89 D) -1.63

Thirty-five math majors, 56 music majors and 26 history majors are randomly selected from 403 math majors, 315 music majors and 512 history majors at the state university. What sampling technique is used? A) cluster B) convenience C) systematic D) simple random E) stratified

Classes are categories into which data are

grouped.When a data set consists of a large number of different discrete data values or when a data set consists of continuous data, we must create classes by using intervals of number

A history professor decides to give a 12-question true-false quiz. She wants to choose the passing grade such that the probability of passing a student who guesses on every question is less than 0.10. What score should be set as the lowest passing grade? A) 9 B) 10 C) 7 D) 8

A medical journal published the results of an experiment on anorexia. The experiment investigated the effects of a controversial new therapy for anorexia. Researchers measured the anorexia levels of 79 adult women who suffer moderate conditions of the disorder. After the therapy, the researchers again measured the women's anorexia levels. The differences between the the pre- and post-therapy anorexia levels were reported. Identify the experimental units. A) the 79 adult women who suffer from anorexia B) the therapy time period (pre or post) C) the disorder (anorexia or no anorexia) D) the differences between the pre- and post-therapy anorexia levels

A new phone system was installed last year to help reduce the expense of personal calls that were being made by employees. Before the new system was installed, the amount being spent on personal calls follows a normal distribution with an average of $900 per month and a standard deviation of $50 per month. Refer to such expenses as PCE's (personal call expenses). Find the point in the distribution below which 2.5% of the PCE's fell. A) $802.00 B) $998.00 C) $877.50 D) $22.50

A poll is conducted in which professional musicians are asked their ages. A) observational study B) experiment

Find the area under the standard normal curve to the left of z = 1.5. A) 0.9332 B) 0.5199 C) 0.0668 D) 0.7612

In a recent survey of drinking laws, a random sample of 1000 women showed that 65% were in favor of increasing the legal drinking age. In a random sample of 1000 men, 60% favored increasing the legal drinking age. Construct a 95% confidence interval for p1 - p2. A) (0.008, 0.092) B) (-2.153, 1.679) C) (-1.423, 1.432) D) (0.587, 0.912)

In a recent survey, 70% of the community favored building a health center in their neighborhood. If 14 citizens are chosen, find the probability that exactly 9 of them favor the building of the health center. A) 0.196 B) 0.007 C) 0.700 D) 0.643

In a study of feeding behavior, zoologists recorded the number of grunts of a warthog feeding by a lake in a 15 minute time period following the addition of food. The data showing the weekly number of grunts and the age of the warthog (in days) are listed below. Compute the sum of the squared residuals of the least squared line for the given data. A) 5533.53 B) 74.39 C) 188.84

In an area of the Great Plains, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). Which is the best predicted value for y given x = 7.1? A) 35.4 B) 35.2 C) 35.7 D) 35.9

In distributions that are skewed to the left, what is the relationship of the mean, median, and mode? A) mode > median > mean B) mode < mean < median C) mean > median > mode D) mode > mean > median

The colors of book covers on a bookshelf A) qualitative B) quantitative

We believe that 95% of the population of all Calculus I students consider calculus an exciting subject. Suppose we randomly and independently selected 20 students from the population. If the true percentage is really 95%, find the probability of observing 19 or more of the students who consider calculus to be an exciting subject in our sample of 20. A) 0.735840 B) 0.377354 C) 0.358486 D) 0.264160

The business college computing center wants to determine the proportion of business students who have personal computers (PC's) at home. If the proportion exceeds 30%, then the lab will scale back a proposed enlargement of its facilities. Suppose 250 business students were randomly sampled and 75 have PC's at home. Find the rejection region for this test using α = 0.05. A) Reject H0 if z > 1.645. B) Reject H0 if z = 1.645. C) Reject H0 if z < -1.645. D) Reject H0 if z > 1.96 or z < -1.96.

A dice game involves throwing three dice and betting on one of the six numbers that are on the dice. The game costs $11 to play, and you win if the number you bet appears on any of the dice. The distribution for the outcomes of the game (including the profit) is shown below: Find your expected profit from playing this game. A) $11.20 B) -$1.53 C) $5.96 D) $0.50

The area under the graph of every Student's t-distribution is A) Less than the standard normal distribution B) 1 C) Greater than the standard normal distribution D) Area of the standard normal distribution

The below table shows the probabilities generated by rolling one die 50 times and noting the up face. What is the probability of getting an odd up face? Roll 1 2 3 4 5 6 Probability 0.22 0.10 0.18 0.12 0.18 0.20 A) 0.42 B) 0.58 C) 0.50 D) 0.55

The commuting times of ten employees (in minutes) are listed below. Find the mode score. 65 66 67 66 67 70 67 70 71 68 A) 66 minutes B) 67 minutes C) 65 minutes D) 68 minutes

The cost of a road atlas A) continuous B) discrete

The regression line for the given data is y ^ = 5.044x + 56.11. Determine the residual of a data point for which x =6 and y = 90. A) 176.374 B) 3.626 C) -504.07 D) 86.374

the pressure of water coming out of a fire hose A) discrete B) continuous

the speed of a car on a Boston tollway during rush hour traffic A) discrete B) continuous

the speed of a car on a New York tollway during rush hour traffic A) discrete B) continuous

An experiment in which neither the experimental unit nor the researcher in contact with the experimental unit knows which treatment the experimental unit is receiving is called a ________________ . A) single-blind experiment B) randomized block design C) double-blind experiment D) matched-pairs design

Construct and Interpret a Confidence Interval for the Population Proportion For example, a 95% level of confidence (α = 0.05) implies that if 100 different confidence intervals are constructed, each based on a different sample from the same population, we will expect

95 of the intervals to contain the parameter and 5 not to include the parameter

Construct and Interpret a Confidence Interval for the Population Mean Constructing a (1− α)100%Confidence Interval for μ

Provided •sample data come from a simple random sample or randomized experiment, •sample size is small relative to the population size (n ≤ 0.05N), and •the data come from a population that is normally distributed, or the sample size is large

The class width is the

difference between consecutive lower class limits. The class width of the data given above is 35 − 25 = 10

Because the mean of a random variable represents what we would expect to happen in the long run, it is also called the

expected value, E(X), of the random variable

The alternative hypothesis, denoted H1, is a statement that we are trying to find evidence

to support

A bicycle manufacturer produces four different bicycle models. Information is summarized in the table below: Model Series Number Weight Style Ascension Ā20 32 Mountain Road Runner B640 21 Road All Terrain C300 27 Hybrid Class Above D90 15 Racing Identify the variables and determine whether each variable is quantitative or qualitative. A) series number: quantitative; weight: quantitative; style: qualitative B) series number: qualitative; weight: qualitative; style: qualitative C) series number: qualitative; weight: quantitative; style: qualitative D) series number: quantitative; weight: qualitative; style: qualitative

A group of students were asked if they carry a n ATM card The responses are listed in the table. If a student is selected at random, find the probability that he or she owns an ATM card given that the student is a freshman. Round your answer to three decimal places. Round your answer to the nearest thousandth. A) 0.719 B) 0.317 C) 0.683 D) 0.410

Find the z-score for which the area under the standard normal curve to its right is 0.07. A) 1.39 B) 1.26 C) 1.45 D) 1.48

The ______________ hypothesis contains the "=" sign. A) conditional B) explanatory C) alternative D) null

Relation Between the Mean, Median, and Distribution Shape Distribution Shape Mean versus Median Symmetric

Mean roughly equal to median

Find the area under the standard normal curve between z = 0 and z = 3. A) 0.4987 B) 0.0010 C) 0.9987 D) 0.4641

the number of emails received on any given day A) discrete B) continuous

the numbers on the shirts of a boy's football team A) qualitative B) quantitative

A baseball player is asked to swing at pitches in sets of four. The player swings at 100 sets of 4 pitches. The probability distribution for hitting a particular number of pitches is given below. Determine the standard deviation for this discrete probability distribution. x 0 1 2 3 4 P(x) 0.02 0.07 0.22 0.27 0.42 A) 1.10 B) 1.05 C) 0.28 D) 1.21

If the graph of a distribution of data shows that the graph is skewed to the left then the: A) No conclusion about the relative position of the mean and the median can be made B) Median > Mean C) Mean > Median D) Mean ≈ Median

True or False: When constructing a confidence interval for the difference of two population proportions, a pooled estimate of p is not required. A) False B) True

Which measure of central tendency is more representative of the typical observation if the graph of the data is skewed to the left? A) Mean B) Median C) Mode D) Midrange

Find the area under the standard normal curve between z = 1.5 and z = 2.5. A) 0.0606 B) 0.9332 C) 0.9816 D) 0.9938

Four Outcomes from Hypothesis Testing

1.Reject the null hypothesis when the alternative hypothesis is true. This decision would be correct. 2.Do not reject the null hypothesis when the null hypothesis is true. This decision would be correct.

A hypothesis test is a "two-tailed" if the alternative hypothesis contains a _______ sign. A) ≠ B) < C) + D) >

Assume that the random variable X is normally distributed, with mean μ = 90 and standard deviation σ = 12. Compute the probability P(57 < X < 105). A) 0.8914 B) 0.8944 C) 0.7888 D) 0.8819

Suppose that E and F are two events and that N(E and F) = 290 and N(E) = 650. What is P(F E)? A) 0.446 B) 0.045 C) 0.309 D) 2.241

The low temperature in degrees Fahrenheit on January 1st in Cheyenne, Wyoming A) continuous B) discrete

True or False: The area under the normal curve drawn with regard to the population parameters is the same as the proportion of the population that has these characteristics. A) True B) False

To find sample size with margin of error using upper and lower fence

Add total of fences and divide by 2 n= P x (1-p) x (Z/a2/E)^2

Draw a normal curve with μ = 160 and σ = 20. Label the mean and the inflection points. A B C D

The heights of ten male students (in inches) in a college biology class are listed below. Find the mean. 71 67 67 72 76 72 73 68 72 72 A) 67 inches B) 72 inches C) 68 inches D) 71 inches

) Find the area under the standard normal curve between z = 1 and z = 2. A) 0.8413 B) 0.1359 C) 0.2139 D) 0.5398

What is the best point estimate for p in order to construct a confidence interval for p? A) μp B) p^ C) p~ D) p

B) p^

Use the regression equation to predict the value of y for x = -4.2. A) -8.255 B) 4.415 C) -9.359 D) -0.221

If we do not reject the null hypothesis when the null hypothesis is in error, then we have made a A) Correct decision B) Type I error C) Type β error D) Type II error

A lobbyist for the oil industry assigns a number to each senator and then uses a computer to randomly generate ten numbers. The lobbyist contacts the senators corresponding to these numbers. What sampling technique was used? A) systematic B) cluster C) stratified D) convenience E) simple random

Computing Probability Using the Classical Method

If an experiment has n equally likely outcomes and if the number of ways that an event E can occur is m, then the probability of E, P(E) is

Finding Quartiles

Step 1: Arrange the data in ascending order. Step 2: Determine the median, M, or second quartile, Q2 .Step 3: Divide the data set into halves: the observations below (to the left of) M and the observations above M. The first quartile, Q1, is the median of the bottom half, and the third quartile, Q3, is the median of the top half

The level of confidence represents the expected proportion of intervals that will contain the parameter if a large number of different samples is obtained.

The level of confidence is denoted (1 −α) · 100%

A frequency distribution

an arrangement of data that indicates how often a particular score or observation occurs

uniform shape

mean and median are equal

3 Find the sample size needed for estimating a population proportion within a given margin of error

n= z crtical ----------- ^2 x P x (1-P) ME

A continuous random variable is normally distributed, or has a normal probability distribution, if its relative frequency histogram of the random variable has the shape of a

normal curve (bell-shaped and symmetric)

A confidence interval for an unknown parameter consists of an interval of numbers based on a

point estimate.

Explain the Completely Randomized Design and matched pairs

randomly assigned to a treatment

The population standard deviation of a variable is the

square root of the sum of squared deviations about the population mean divided by the number of observations in the population, N. That is, it is the square root of the mean of the squared deviations about the population mean.The population standard deviation is symbolically represented by σ (lowercase Greek sigm

The sample standard deviation, s, of a variable is the

square root of the sum of squared deviations about the sample mean divided by n− 1, where n is the sample size

A single-blind experiment is one in which the experimental unit (or subject) does not know

which treatment he or she is receiving.

A probability density function (pdf) is an equation used to compute probabilities of continuous random variables. It must satisfy the following two properties

1.The total area under the graph of the equation over all possible values of the random variable must equal 1. 2.The height of the graph of the equation must be greater than or equal to 0 for all possible values of the random variabl

A certain disease only affects men 20 years of age or older. The chart shows the probability that a man with the disease falls in the given age group. What is the probability that a randomly selected man with the disease is not between the ages of 55 and 64? Age Group Probability 20-24 0.004 25-34 0.006 35-44 0.14 45-54 0.29 55-64 0.32 65-74 0.17 75+ 0.07 A) 0.68 B) 0.24 C) 0.32 D) 0.29

A researcher obtained a random sample of 100 smokers and a random sample of 100 nonsmokers. After interviewing all 200 participants in the study, the researcher compared the rate of depression among the smokers with the rate of depression among nonsmokers. A) observational study B) experiment

Determine the area under the standard normal curve that lies between: z = 0.8 and z = 1.4 A) 0.1311 B) 0.9192 C) 0.7881 D) 0.2119

To construct a confidence interval for the difference of two population proportions the samples must be independently obtained random samples, both must consist of less than 5% of the population, and A) both np ^ 1 (1 - p ^ 1) ≥ 10 and np ^ 2 (1 - p ^ 2) ≥ 10 must be true. B) np ^ 1 (1 - p ^ 1) + np ^ 2 (1 - p ^ 2) ≥ 20. C) only one of np ^ 1 (1 - p ^ 1) ≥ 10 or np ^ 2 (1 - p ^ 2) ≥ 10 must be true. D) np ^ 1 (1 - p ^ 1) np ^ 2 (1 - p ^ 2) ≥ 100.

To eliminate the effects of either the row or the column variables in a contingency table, a_____________distribution is created. A) marginal B) Student's t C) χ2 D) normalized

Classify the two given samples as independent or dependent. Sample 1: Pre-training blood pressure of 23 people Sample 2: Post-training blood pressure of 23 people A) independent B) dependent

Classify the two given samples as independent or dependent. Sample 1: The heights in inches of 16 newborn females Sample 2: The heights in inches of 16 newborn males A) dependent B) independent

Classify the two given samples as independent or dependent. Sample 1: The scores of 26 students who took a statistics final Sample 2: The scores of 26 different students who took a physics final A) dependent B) independent

Find the standardized test statistic, z to test the hypothesis that p1 = p2. Use α = 0.05. The sample statistics listed below are from independent samples. Sample statistics: n1 = 50, x1 = 35, and n2 = 60, x2 = 40 A) 2.361 B) 0.374 C) 0.982 D) 1.328

Find the t-value such that the area in the right tail is 0.2 with 5 degrees of freedom. A) -0.92 B) 0.920 C) 0.941 D) 2.757

Find the test statistic, t, to test the hypothesis that μ1 < μ2. Two samples are randomly selected and come from populations that are normal. The sample statistics are given below. n1 = 15 n2 = 15 x1 = 21.14 x2 = 23.69 s1 = 2.9 s2 = 2.8 A) -0.669 B) -2.450 C) -3.165 D) -1.667

In the game of craps two dice are rolled and the up faces are totaled. If the person rolling the dice on the first roll rolls a 7 or an 11 total they win. If they roll a 2, 3, or 12 on the first roll they lose. If they roll any other total then on subsequent rolls they must roll that total before rolling a 7 to win. What is the probability of winning on the first roll? A) 0.50 B) 0.22 C) 0.17 D) 0.06

The highest point on the graph of the normal density curve is located at A) μ + 3σ B) its mean C) μ + σ D) an inflection point

The number of violent crimes committed in a city on a given day in a random sample of 100 days is a __________ random variable. A) continuous B) discrete

The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1100 miles. What is the probability a particular tire of this brand will last longer than 58,900 miles? A) 0.1587 B) 0.8413 C) 0.7266 D) 0.2266

the weights of cases loaded onto an airport conveyor belt A) qualitative B) quantitative

The sampling distribution of the sample mean is shown. If the sample size is n = 25, what is the standard deviation of the population from which the sample was drawn? Round to the nearest thousandth where appropriate. 7.94 8 8.06 A) σ = 1.5 B) σ = 0.3 C) σ = 0.002 D) σ = 0.012

B) To find , squ rt of 25 x sd

A drug company wanted to test a new acne medication. The researchers found 400 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose acne symptoms decreased was recorded and compared. Identify the experimental units. A) the drug (medication or placebo) B) the percentage who had decreased acne symptoms C) the 400 adults aged 25-35 D) the one month treatment time

Calculate the linear correlation coefficient for the data below A) -0.581 B)-0.549 C) -0.104 D) -0.132

Find the area under the standard normal curve to the right of z = -1.25. A) 0.7193 B) 0.5843 C) 0.8944 D) 0.6978

A quiz consists of 10 true or false questions. To pass the quiz a student must answer at least eight questions correctly. If the student guesses on each question, what is the probability that the student will pass the quiz? A) 0.20 B) 0.08 C) 0.8 D) 0.055

A survey of 100 fatal accidents showed that in 11 cases the driver at fault was inadequately insured. Find a point estimate for p, the population proportion of accidents where the driver at fault was inadequately insured A) 0.099 B) 0.89 C) 0.124 D) 0.11

Find the critical value for a two-tailed test with α = 0.01. A) ±2.33 B) ±1.96 C) ±1.645 D) ±2.575

The mean age of judges in Dallas is greater than 45.9 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is not sufficient evidence to reject the claim μ > 45.9. B) There is sufficient evidence to support the claim μ > 45.9. C) There is sufficient evidence to reject the claim μ > 45.9. D) There is not sufficient evidence to support the claim μ > 45.9.

The weekly salaries (in dollars) of randomly selected employees of a company are summarized in the boxplot below. Based on the boxplot, is a large sample necessary to conduct a hypothesis test about the mean salary? If so, why? A) No; data appear to be normally distributed. B) Yes; data contain outliers. C) Yes; data do not appear to be normally distributed but skewed left. D) Yes; data do not appear to be normally distributed but skewed right.

residual for a point

The difference between the observed value of y and the predicted value of y is the error,

Binomial Probability Distribution Function

The probability of obtaining x successes in n independent trials of a binomial experiment is given b

9.1 Obtain a point estimate for the population proportion.

To Find : x ------- n

A ______________ is a statement or claim regarding a characteristic of one or more populations. A) hypothesis B) conjecture C) fact D) conclusion

A candidate for state representative of a certain state claims to be favored by at least half of the voters. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is not sufficient evidence to reject the claim p ≥ 0.5. B) There is sufficient evidence to support the claim p ≥ 0.5. C) There is sufficient evidence to reject the claim p ≥ 0.5. D) There is not sufficient evidence to support the claim p ≥ 0.5

A farmer was interested in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 52 or fewer flights or 60 or more flights on average in the next 40 rows down which he drives his tractor? A) 0.0612 B) 0.0530 C) 0.4959 D) 0.9388

Many people think that a national lobby's successful fight against gun control legislation is reflecting the will of a minority of Americans. A random sample of 4000 citizens yielded 2230 who are in favor of gun control legislation. Find the point estimate for estimating the proportion of all Americans who are in favor of gun control legislation. A) 0.5575 B) 0.4425 C) 2230 D) 4000

the temperatures of cups of coffee served at a restaurant A) quantitative B) qualitative

Assume that the random variable X is normally distributed with mean μ = 50 and standard deviation σ = 12. Find the 40th percentile for X. A) 47 B) 42.08 C) 53 D) 44.6

A) To Find- Convert to decimal, find z-score z score x sd + mean

Suppose a uniform random variable can be used to describe the outcome of an experiment with the outcomes ranging from 10 to 70. What is the probability that this experiment results in an outcome less than 20? A) 0.17 B) 1 C) 0.22 D) 0.13

A) To Find: 10-20 ------=0.167=0.17 10-70

Professor Whata Guy surveyed a random sample of 420 statistics students. One of the questions was "Will you take another mathematics class?" The results showed that 252 of the students said yes. What is the sample proportion, p^of students who say they will take another math class? A) 0.6 B) 0.775 C) 0.252 D) 0.42

A) To find: 252/420

A card is drawn from a standard deck of 52 playing cards. Find the probability that the card is a queen or a club. Express the probability as a simplified fraction. A) 3/13 B) 4/13 C) 7/52 D) 2/13

A computer package was used to generate the following printout for estimating the sale price of condominiums in a particular neighborhood. X = sale_price SAMPLE MEAN OF X = 46,400 SAMPLE STANDARD DEV = 13,747 SAMPLE SIZE OF X = 15 CONFIDENCE = 95 UPPER LIMIT = 54,013.60 SAMPLE MEAN OF X = 46,400 LOWER LIMIT = 38,786.40 A friend suggests that the mean sale price of homes in this neighborhood is $51,000. Comment on your friend's suggestion. A) Your friend is wrong, and you are 95% certain. B) Based on this printout, all you can say is that the mean sale price might be $51,000. C) Your friend is correct, and you are 95% certain. D) Your friend is correct, and you are 100% certain.

A doctor at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she desires to be 90% confident that her estimate is within 3 ounces of the true mean? Assume that s = 6 ounces based on earlier studies. A) 10 B) 11 C) 4 D) 3

A farmer wishes to test the effects of a new fertilizer on her potato yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four C's are treated with no fertilizer. At harvest time, the potato yield is recorded for each section of land. What type of experimental design is this? A) completely randomized design B) randomized block design C) matched-pairs design D) double-blind design

A group of 79 students were asked how far they commute to work from home each time they go to work from home. The results are given below. Determine the first quartile. Miles traveled Frequency 1 1 2 2 3 12 4 18 5 7 6 10 7 10 8 11 9 5 10 3 A) 5 mi B) 4 mi C) 6 mi D) 3 mi

A group of 79 students were asked how far they commute to work from home each time they go to work from home. The results are given below. Would a drive of 15 miles be considered an outlier? Answer Yes or No. Miles traveled Frequency 1 1 2 2 3 12 4 18 5 7 6 10 7 10 8 11 9 5 10 3 A) No B) Yes

A highly selective boarding school will only admit students who place at least 1.5 z-scores above the mean on a standardized test that has a mean of 110 and a standard deviation of 12. What is the minimum score that an applicant must make on the test to be accepted? A) 92 B) 128 C) 122 D) 98

A local bakery has determined a probability distribution for the number of cheesecakes that they sell in a given day. The distribution is as follows: Number sold in a day 0 5 10 15 20 Prob (Number sold) 0.08 0.05 0.25 0.22 0.4 Find the number of cheesecakes that this local bakery expects to sell in a day. A) 14.13 B) 14.05 C) 14.45 D) 10

A manager asked her employees how many times they had given blood in the last year. The results of the survey are given below. The random variable x represents the number of times a person gave blood and P(x) represents the probability of selecting an employee who had given blood that percent of the time. What is the mean number of times a person gave blood based on this survey? x 0 1 2 3 4 5 6 P(x) 0.30 0.25 0.20 0.12 0.07 0.04 0.02 A) 3.0 B) 1.6 C) 2.0 D) 0.14

A manager at a local company asked his employees how many times they had given blood in the last year. The results of the survey are given below. The random variable x represents the number of times a person gave blood and P(x) represents the probability of selecting an employee who had given blood that percent of the time. What is the standard deviation for the number of times a person gave blood based on this survey? A) 1.16 B) 1.54 C) 1.82 D) 2.23

A medical researcher obtains a sample of adults suffering from diabetes. She randomly assigns 73 people to a treatment group and 73 to a placebo group. The treatment group receives a medication over a period of three months and the placebo group receives a placebo over the same time frame. At the end of three months the patients' symptoms are evaluated. A) observational study B) experiment

A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 470 seconds and a standard deviation of 60 seconds. Between what times do we expect most (approximately 95%) of the boys to run the mile? A) between 0 and 568.736 sec B) between 352.4 and 587.6 sec C) between 371.3 and 568.736 sec D) between 375 and 565 sec

A random sample of 10 parking meters in a resort community showed the following incomes for a day. Assume the incomes are normally distributed. Find the 95% confidence interval for the true mean. Round to the nearest cent. $3.60 $4.50 $2.80 $6.30 $2.60 $5.20 $6.75 $4.25 $8.00 $3.00 A) ($2.11, $5.34) B) ($3.39, $6.01) C) ($1.35, $2.85) D) ($4.81, $6.31)

A scientist was studying the effects of a new fertilizer on crop yield. She randomly assigned half of the plots on a farm to group one and the remaining plots to group two. On the plots in group one, the new fertilizer was used for a year. On the plots in group two, the old fertilizer was used. At the end of the year the average crop yield for the plots in group one was compared with the average crop yield for the plots in group two. A) observational study B) experiment

A seed company has a test plot in which it is testing the germination of a hybrid seed. They plant 50 rows of 40 seeds per row. After a two-week period, the researchers count how many seed per row have sprouted. They noted that least number of seeds to germinate was 33 and some rows had all 40 germinate. The germination data is given below in the table. The random variable x represents the number of seed in a row that germinated and P(x) represents the probability of selecting a row with that number of seed germinating. Determine the standard deviation of the number of seeds per row that germinated. A) 7.13 B) 1.51 C) 36.86 D) 6.07

Given a distribution that follows a standard normal curve, what does the graph of the curve do as z increases in the positive direction? A) The graph of the curve eventually intersects the horizontal axis. B) The graph of the curve approaches zero. C) The graph of the curve approaches an inflection point. D) The graph of the curve approaches 1.

Given the equation of a regression line is y= 5x - 10, what is the best predicted value for y given x = 2? A) 20 B) 0 C) 15 D) -3

Given the following five-number summary, find the interquartile range. 29, 37, 50, 66, 94 A) 50 B) 29 C) 65 D) 32.5

Given the table of probabilities for the random variable x, does this form a probability distribution? Answer Yes or No A) Yes B) No

Given the table of probabilities for the random variable x, does this form a probability distribution? Answer Yes or No. A) No B) Yes

Health care issues are receiving much attention in both academic and political arenas. A sociologist recently conducted a survey of citizens over 60 years of age whose net worth is too high to qualify for government health care but who have no private health insurance. The ages of 25 uninsured senior citizens were as follows: 68 73 66 76 86 74 61 89 65 90 69 92 76 62 81 63 68 81 70 73 60 87 75 64 82 Suppose the mean and standard deviation are 74.0 and 9.7, respectively. If we assume that the distribution of ages is bell shaped, what percentage of the respondents will be between 64.3 and 93.4 years old? A) approximately 83.9% B) approximately 81.5% C) approximately 68% D) approximately 95%

Parking at a large university has become a very big problem. University administrators are interested in determining the average parking time (e.g. the time it takes a student to find a parking spot) of its students. An administrator inconspicuously followed 210 students and carefully recorded their parking times. Identify the sample of interest to the university administration. A) parking time of a student B) parking times of the 210 students C) location of the parking spot D) type of car (import or domestic)

Select a random sample of five state capitals from the list below using the two digit list of random numbers provided. Begin with the uppermost left random number and proceed down each column. When a column is complete, use the numbers at the top of the next right column and proceed down that column. State Capitals A) Boston, MA; Concord, NH; Dover DE; Santa Fe, NM; Richmond, VA. B) Springfield, IL; Atlanta,GA; Providence, RI; Santa Fe, NM; Columbus OH. C) Springfield, IL; Des Moines, IA; Boston, MA; Santa Fe, NM; Columbus OH. D) Carson City NV; Boise ID; Atlanta, GA; Cheyenne, WY; Boston, MA.

Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.14 onces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains more than 12.14 ounces of beer. A) 1 B) 0.5 C) 0 D) 0.4

Suppose a population has a mean weight of 180 pounds and a standard deviation of 25 pounds. A sample of 100 items is drawn from this population. What is the standard error of the mean? A) 18.0 B) 2.5 C) 1.8 D) 0.25

The amount of money collected by a snack bar at a large university has been recorded daily for the past five years. Records indicate that the mean daily amount collected is $3650 and the standard deviation is $600. The distribution is skewed to the right due to several high volume days (including football game days). Suppose that 100 days were randomly selected from the five years and the average amount collected from those days was recorded. Which of the following describes the sampling distribution of the sample mean? A) skewed to the right with a mean of $3650 and a standard deviation of $600 B) normally distributed with a mean of $3650 and a standard deviation of $60 C) normally distributed with a mean of $3650 and a standard deviation of $600 D) normally distributed with a mean of $365 and a standard deviation of $60

The amount of soda a dispensing machine pours into a 12 ounce can of soda follows a normal distribution with a mean of 12.24 ounces and a standard deviation of 0.16 ounce. The cans only hold 12.40 ounces of soda. Every can that has more than 12.40 ounces of soda poured into it causes a spill and the can needs to go through a special cleaning process before it can be sold. What is the probability a randomly selected can will need to go through this process? A) 0.8413 B) 0.1587 C) 0.3413 D) 0.6587

The amount of soda a dispensing machine pours into a 12 ounce can of soda follows a normal distribution with a standard deviation of 0.14 ounce. Every can that has more than 12.35 ounces of soda poured into it causes a spill and the can needs to go through a special cleaning process before it can be sold. What is the mean amount of soda the machine should dispense if the company wants to limit the percentage that need to be cleaned because of spillage to 3%? A) 12.6132 oz B) 12.0868 oz C) 12.6538 oz D) 12.0462 oz

The amount of television viewed by today's youth is of primary concern to Parents Against Watching Television (PAWT). 300 parents of elementary school-aged children were asked to estimate the number of hours per week that their child watched television. The mean and the standard deviation for their responses were 14 and 4,respectively. PAWT constructed a stem-and-leaf display for the data that showed that the distribution of times was a bell-shaped distribution. Give an interval around the mean where you believe most (approximately 95%) of the television viewing times fell in the distribution. A) less than 10 and more than 18 hours per week B) between 6 and 22 hours per week C) between 10 and 18 hours per week D) between 2 and 26 hours per week

The distribution of Bachelor's degrees conferred by a university is listed in the table. Assume that a student majors in only one subject. What is the probability that a randomly selected student with a Bachelor's degree majored in Business, Chemistry or Engineering? Round your answer to three decimal places. Major Frequency Physics 216 Philosophy 207 Engineering 86 Business 180 Chemistry 227 A) 0.462 B) 0.538 C) 0.290 D) 0.342

The least squares regression line A) maximizes the mean difference between the residuals squared. B) minimizes the sum of the residuals squared. C) maximizes the sum of the residuals squared. D) minimizes the mean difference between the residuals squared

The mean monthly gasoline bill for one household is greater than $110. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is not sufficient evidence to reject the claim μ > $110. B) There is sufficient evidence to support the claim μ > $110. C) There is not sufficient evidence to support the claim μ > $110. D) There is sufficient evidence to reject the claim μ > $110.

The weights (in pounds) of babies born at St Mary's hospital last month are summarized in the table. Weight (lb) Number of Babies 5.0 - 5.8 8 5.9 - 6.7 20 6.8 - 7.6 18 7.7 - 8.5 10 8.6 - 9.4 4 Find the class limits for the second class. A) lower limit: 5.85; upper limit:6.75 B) lower limit: 5.9; upper limit: 6.7 C) lower limit: 5.8; upper limit: 6.8 D) lower limit: 5.9; upper limit: 6.8

True or False: The area under the normal curve drawn with regard to the population parameters is the same as the probability that a randomly selected individual of a population has these characteristics. A) False B) True

True or False? When choosing the sample size for estimating a population proportion p to within E units with confidence (1 - α)100%, if you take p ≈ 0.5 as the approximation to p, you will always obtain a sample size that is at least as large as required. A) False B) True

Use the spinner below to answer the question. Assume that it is equally probable that the pointer will land on any one of the five numbered spaces. If the pointer lands on a borderline, spin again. Find the probability that the arrow will land on an odd number. A) 2/5 B) 3/5 C) 0 D) 1

When results from a scholastic assessment test are sent to test-takers, the percentiles associated with their scores are also given. Suppose a test-taker scored at the 96th percentile for their verbal grade and at the 37th percentile for their quantitative grade. Interpret these results. A) This student performed better than 96% of the other test-takers in the verbal part and better than 63% in the quantitative part. B) This student performed better than 96% of the other test-takers in the verbal part and better than 37% in the quantitative part. C) This student performed better than 4% of the other test-takers in the verbal part and better than 63% in the quantitative part. D) This student performed better than 4% of the other test-takers in the verbal part and better than 37% in the quantitative part.

capacity of a backpack A) ordinal B) ratio C) nominal D) interval

he data set: weekly grocery bills (in dollars) for 20 randomly selected households 135 120 115 132 136 124 119 145 98 110 125 120 115 130 140 105 116 121 125 108 A) skewed to the right B) bell shaped C) uniform D) skewed to the left

he degrees of freedom used when testing two independent samples where the population standard deviation is unknown is A) n1 + n2 - 1. B) the smaller of n1 - 1 or n2 - 1. C) the larger of n1 - 1 or n2 - 1. D) n1 + n2 - 2.

the bank account numbers of the students in a class A) quantitative B) qualitative

the musical instrument played by a music student A) ratio B) nominal C) interval D) ordinal

the native language of a tourist A) ordinal B) nominal C) interval D) ratio

A simple random sample of size n = 1100 is obtained from a population whose size is N = 1,600,000 and whose population proportion with a specified characteristic is p = 0.65. Describe the sampling distribution of p ^ . A) Exactly normal; μp = 0.65, σp = 0.014 B) Approximately normal; μp = 0.65, σp = 0.014 C) Exactly normal; μp = 0.65, σp = 0.1192 D) Approximately normal; μp = 0.65, σp = 0.1192

B) ---------- To find sq rt / 0.6 x (1-0.6)/ 1100

Researchers wanted to determine whether there was an association between city driving and stomach ulcers. They selected a sample of 900 young adults and followed them for a twenty-year period. At the start of the study none of the participants was suffering from a stomach ulcer. Each person kept track of the number of hours per week they spent driving in city traffic. At the end of the study each participant underwent tests to determine whether they were suffering from a stomach ulcer. The researchers analyzed the results to determine whether there was an association between city driving and stomach ulcers. A) retrospective; Individuals are asked to look back in time. B) cohort; Individuals are observed over a long period of time. C) cross-sectional; Information is collected at a specific point in time.

B) cohort; Individuals are observed over a long period of time.

Vitamin D is important for the metabolism of calcium and exposure to sunshine is an important source of vitamin D. A researcher wanted to determine whether osteoperosis was associated with a lack of exposure to sunshine. He selected a sample of 250 women with osteoperosis and an equal number of women without osteoperosis. The two groups were matched - in other words they were similar in terms of age, diet, occupation, and exercise levels. Histories on exposure to sunshine over the previous twenty years were obtained for all women. The total number of hours that each woman had been exposed to sunshine in the previous twenty years was estimated. The amount of exposure to sunshine was compared for the two groups. A) cross-sectional; Information is collected at a specific point in time. B) retrospective; Individuals are asked to look back in time C) cohort; Individuals are observed over a long period of time.

B) retrospective; Individuals are asked to look back in time

A farmer wishes to test the effects of a new fertilizer on her wheat yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four C's are treated with no fertilizer. At harvest time, the wheat yield is recorded for each section of land. Identify the experimental units. A) the three types of fertilizer B) the wheat plants on the various plots of land C) the four types of soil D) the wheat yield at harvest time

B) the wheat plants on the various plots of land

A pollster wishes to estimate the number of left-handed scientists. How large a sample is needed in order to be 95% confident that the sample proportion will not differ from the true proportion by more than 3%? A previous study indicates that the proportion of left-handed scientists is 9%. A) 14 B) 247 C) 350 D) 385

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial aid to within 1% with 98% reliability, how many students would need to be sampled? A) 5637 B) 132 C) 13,133 D) 3177

Assume that the random variable X is normally distributed, with mean μ = 110 and standard deviation σ = 20. Compute the probability P(X > 126). A) 0.1977 B) 0.7881 C) 0.2119 D) 0.2420

Assume that the random variable X is normally distributed, with mean μ = 80 and standard deviation σ = 8. Compute the probability P(X < 90). A) 0.9015 B) 0.1056 C) 0.8944 D) 0.8849

The commute times (in minutes) of 30 employees are listed below. Find Q3. 31 41 45 48 52 55 56 56 63 65 67 67 69 70 70 74 75 78 79 79 80 81 83 85 85 87 90 92 95 99 A) 56 min B) 72 min C) 83 min D) 82 min

The data below are the final exam scores of 10 randomly selected history students and the number of hours they slept the night before the exam. Find the equation of the regression line for the given data. What would be the predicted score for a history student who slept 7 hours the previous night? Is this a reasonable question? Round the regression line values to the nearest hundredth, and round the predicted score to the nearest whole number. A) y= -5.04x + 56.11; 21; Yes, it is reasonable. B) y= 5.04x + 56.11; 91; No, it is not reasonable. 7 hours is well outside the scope of the model. C) y= 5.04x + 56.11; 91; Yes, it is reasonable. D) y= -5.04x + 56.11; 21; No, it is not reasonable. 7 hours is well outside the scope of the model

The regression line for the given data is y ^ = 2.097x - 0.552. Determine the residual of a data point for which x =-2 and y = -6. A) 11.134 B) -10.746 C) -1.254 D) -4.746

Comparing z-distibution to t-distribution

CONCLUSION: •The histogram for z is symmetric and bell-shaped with the center of the distribution at 0 and virtually all the rectangles between −3 and 3. In other words, z follows a standard normal distribution CONCLUSION: •The histogram for t is also symmetric and bell-shaped with the center of the distribution at 0, but the distribution of t has longer tails (i.e., t is more dispersed), so it is unlikely that t follows a standard normal distribution. The additional spread in the distribution of t can be attributed to the fact that we use s to find t instead of σ. Because the sample standard deviation is itself a random variable (rather than a constant such as σ), we have more dispersion in the distribution of t.

A brewery has a beer dispensing machine that dispenses beer into the company's 12 ounce bottles. The distribution for the amount of beer dispensed by the machine follows a normal distribution with a standard deviation of 0.11 ounce. The company can control the mean amount of beer dispensed by the machine. What value of the mean should the company use if it wants to guarantee that 98.5% of the bottles contain at least 12 ounces (the amount on the label)? Round to the nearest thousandth. A) 12.002 oz B) 12.001 oz C) 12.267 oz D) 12.239 oz

A city council randomly selects 1000 married couples from a certain city and records the number of women who are in favor of a new football stadium and the number of men who are in favor. A) quantitative, independent B) quantitative, dependent C) qualitative, independent D) qualitative, dependent

A drug company wanted to test a new acne medication. The researchers found 600 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose acne symptoms decreased was recorded and compared. How many levels does the treatment in this experiment have? A) 600 (number of respondents) B) 1 (months of treatment) C) 10 (age span of respondents) ' D) 2 (medication or placebo)

A drug company wanted to test a new indigestion medication. The researchers found 600 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose indigestion symptoms decreased was recorded and compared. What is the response variable in this experiment? A) the type of drug (medication or placebo) B) the one month treatment time C) the 600 adults aged 25-35 D) the percentage who had decreased indigestion symptoms

A national caterer determined that 37% of the people who sampled their food said that it was delicious. A random sample of 144 people is obtained from a population of 5000. The 144 people are asked to sample the caterer's food. If p ^ is the sample proportion saying that the food is delicious, what is the standard deviation of the sampling distribution of p ^ ? A) 0.23 B) 0.48 C) 0.002 D) 0.04

A private opinion poll is conducted for a politician to determine what proportion of the population favors adding more national parks. How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the true proportion by more than 3%? A) 22 B) 1509 C) 3684 D) 1842

A university compared the mean salary of its science graduates ten years after graduation with the mean salary of its social science graduates ten years after graduation. A) quantitative, dependent B) qualitative, independent C) qualitative, dependent D) quantitative, independent

According to government data, the probability that an adult was never in a museum is 15%. In a random survey of 10 adults, what is the probability that two or fewer were never in a museum? A) 0.800 B) 0.200 C) 0.002 D) 0.820

According to the Federal Communications Commission, 70% of all U.S. households have vcrs. In a random sample of 15 households, what is the probability that exactly 10 have vcrs? A) 0.7939 B) 0.7 C) 0.5 D) 0.2061

Determine the point estimate of the population mean and margin of error for the confidence interval with lower bound 20 and upper bound: 30. A) x = 30, E = 5 B) x = 20, E = 10 C) x = 25, E = 10 D) x = 25, E = 5

Determine μ x and σ x from the given parameters of the population and the sample size. Round the answer to the nearest thousandth where appropriate. μ = 58, σ = 8, n = 14 A) μx = 58, σx = 0.571 B) μx = 33.486, σx = 2.138 C) μx = 58, σx = 8 D) μx = 58, σx = 2.138

The data below are the final exam scores of 10 randomly selected history students and the number of hours they slept the night before the exam. Find the equation of the regression line for the given data. What would be the predicted score for a history student who slept 15 hours the previous night? Is this a reasonable question? Round your predicted score to the nearest whole number. Round the regression line values to the nearest hundredth. A) y ^ = -5.04x + 56.11; -20; No, it is not reasonable. B) y ^ = -5.04x + 56.11; -20; Yes, it is reasonable. C) y ^ = 5.04x + 56.11; 132; Yes, it is reasonable. D) y ^ = 5.04x + 56.11; 132; No, it is not reasonable. 15 hours is well outside the scope of the model

The heights of 20- to 29-year-old females are known to have a population standard deviation σ = 2.7 inches. A simple random sample of n = 15 females 20 to 29 years old results in the following data: 63.1 67.9 64.8 62.2 65.4 63.3 66.2 68.2 69.7 64.1 68.4 69.9 67.3 64.5 70.2 A) (64.85, 67.85); we are 95% confident that the mean height of 20- to 29-year-old females is between 64.85 and 67.85 inches. B) (65.20, 67.50); we are 95% confident that the mean height of 20- to 29-year-old females is between 65.20 and 67.50 inches. C) (65.12, 67.58); we are 95% confident that the mean height of 20- to 29-year-old females is between 65.12 and 67.58 inches. D) (64.98, 67.72); we are 95% confident that the mean height of 20- to 29-year-old females is between 64.98 and 67.72 inches.

The manager of a used car lot took inventory of the automobiles on his lot and constructed the following table based on the age of his car and its make (foreign or domestic). A car was randomly selected from the lot. Given that the car selected is older than two years old, find the probability that it is not a foreign car A) 57/100 B) 57/112 C) 11/20 D) 55/112

The names of 40 employees are written on 40 cards. The cards are placed in a bag, and three names are picked from the bag. What sampling technique was used? A) cluster B) convenience C) systematic D) simple random E) stratified

Relation Between the Mean, Median, and Distribution Shape Distribution Shape Mean versus Median Skewed right

Mean substantially larger than media

Relation Between the Mean, Median, and Distribution Shape Distribution Shape Mean versus Median Skewed left

Mean substantially smaller than media

Standard Deviation of a Discrete Random Variable

the square root of the variance

The ________ of a variable is computed by determining the sum of all the values of the variable in the data set and dividing this sum by the number of observations in the data set. A) Mode B) Geometric mean C) Median D) Arithmetic mean

The ages of a group of patients being treated at one hospital for osteoporosis are summarized in the frequency histogram below. Based on the histogram, is a large sample necessary to conduct a hypothesis test about the mean age? If so, why? A) No; data appear to be normally distributed with no outliers. B) Yes; data do not appear to be normally distributed but bimodal. C) Yes; data do not appear to be normally distributed but skewed right. D) Yes; data do not appear to be normally distributed but skewed left

A histogram is constructed by

drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. The width of each rectangle is the same and the rectangles touch each other

An experiment in which the experimental unit (or subject) does not know which treatment he or she is receiving is called a ________________ . A) randomized block design B) single-blind experiment C) matched-pairs design D) double-blind experiment

Approximately ____% of the area under the normal curve is between μ - 2σ and μ + 2σ. A) 99.7 B) 95 C) 68 D) 50

Classify the statement as an example of classical probability, empirical probability, or subjective probability. The probability that cab fares will rise during the winter is 0.05. A) empirical probability B) subjective probability C) classical probability

If we reject the null hypothesis when the null hypothesis is true, then we have made a A) Type α error B) Type I error C) Type II error D) Correct decision

the number of bottles of juice sold in a cafeteria during lunch A) continuous B) discrete

the number of goals scored in a hockey game A) continuous B) discrete

A contingency table relates A) only continuous random variables. B) the difference in the means of two random variables. C) two categories of data. D) a particular response with order in which that response should be applied.

Assume that it is equally probable that the pointer will land on any one of the five numbered spaces. If the pointer lands on a borderline, spin again. Find the probability that the arrow will land on 3 or 1. A) 1 B) 1/ 3 C) 2/ 5 D) 3

Calculate the linear correlation coefficient for the data below. A) 0.881 B) 0.792 C) 0.990 D) 0.819

Compare a graph of the normal density function with mean of 0 and standard deviation of 1 with a graph of a normal density function with mean equal to 0 and standard deviation of 0.5. The graphs would A) Have no horizontal displacement but one would be flatter than the other. B) Have the same height but one would be shifted 4 units to the right. C) Have no horizontal displacement but one would be steeper that the other. D) Have the same height but one would be shifter 4 units to the left.

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph can represent a normal density function. B) The graph cannot represent a normal density function because it is not bell shaped. C) The graph cannot represent a normal density function because it does not approach the horizontal axis as x increases or decreases without bound. D) The graph cannot represent a normal density function because it has no inflection points

Many people think that a national lobby's successful fight against gun control legislation is reflecting the will of a minority of Americans. A random sample of 4000 citizens yielded 2250 who are in favor of gun control legislation. Estimate the true proportion of all Americans who are in favor of gun control legislation using a 98% confidence interval. Express the answer in the form p ^± E and round to the nearest ten-thousandth. A) 0.5625 ± 0.5727 B) 0.4375 ± 0.5727 C) 0.5625 ± 0.0182 D) 0.4375 ± 0.0182

Smith is a weld inspector at a shipyard. He knows from keeping track of good and substandard welds that for the afternoon shift 5% of all welds done will be substandard. If Smith checks 300 of the 7500 welds completed that shift, what is the probability that he will find more than 25 substandard welds? A) 0.4960 B) 0.9960 C) 0.0040 D) 0.5040

The average score of all golfers for a particular course has a mean of 70 and a standard deviation of 3.5. Suppose 49 golfers played the course today. Find the probability that the average score of the 49 golfers exceeded 71. A) 0.3707 B) 0.4772 C) 0.0228 D) 0.1293

The number of students enrolled in a physics class for the last ten semesters are listed below. Find the median number of students. 65 66 67 66 67 70 67 70 71 68 A) 66 students B) 68 students C) 67 students D) 70 students

To assess attitudes towards issues that affect the residents of a village, the village randomly chose 800 families to participate in a survey of life attitudes. The village received 628 completed surveys. What is the sample proportion of completed surveys? A) 0.886 B) 1.274 C) 0.785 D) 0.628

To perform a hypothesis test of two population proportions, the pooled estimate of p must be determined. The pooled estimate, p ^ , is A) p ^ = x1 + x2 n1n2 B) p ^ = x1 n1 + x2 n2 C) p ^ = x1 + x2 n1 + n2 D) p ^ = n2x1 + n1x2 n1 + n2

Two dice are rolled. What is the probability of having both faces the same (doubles) or a total of 4 or 10? Round to the nearest hundredth. A) 0.15 B) 0.33 C) 0.28 D) 0.06

Use the following frequency distribution to determine the class limits of the third class. Class Frequency 9-15 5 16-22 9 23-29 6 30-36 3 37-43 7 44-50 4 A) lower limit: 22; upper limit: 30 B) lower limit: 23; upper limit: 30 C) lower limit: 23; upper limit: 29 D) lower limit: 22.5; upper limit: 29.5

__________ is a condition applied to the experimental units involved in an experiment. A) The factor level B) The sampling design C) A treatment D) The design

the day of the month A) nominal B) ordinal C) interval D) ratio

the year of manufacture of a car A) ratio B) ordinal C) interval D) nominal

A farmer wishes to test the effects of a new fertilizer on her soybean yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four C's are treated with no fertilizer. At harvest time, the soybean yield is recorded for each section of land. What is the treatment in this experiment? A) the fertilizers B) the soybean yield recorded for each section of land C) the four types of soil D) the section of land (A, B, or C)

A medical journal published the results of an experiment on depression. The experiment investigated the effects of a controversial new therapy for depression. Researchers measured the depression levels of 79 adult women who suffer moderate conditions of the disorder. After the therapy, the researchers again measured the women's depression levels. The differences between the the pre- and post-therapy depression levels were reported. How many levels does the treatment have in this experiment? A) 2 (pre- and post-therapy) B) 1 (therapy) C) 158 (the adult women who suffer from depression measured pre- and post-therapy) D) 79 (the adult women who suffer from depression)

A simple random sample of size n < 30 for a quantitative variable has been obtained. Using the normal probability plot, the correlation between the variable and expected z-score, and the boxplot, judge whether a t-interval should be constructed. 33) n = 14; Correlation = 0.956 A) Yes B) No

A variable that is related to either the response variable or the predictor variable or both, but which is excluded from the analysis is a A) lurking variable. B) discrete variable. C) random variable. D) qualitative variable.

After completing an inventory of three warehouses, a golf club shaft manufacturer described its stock of 12,246 shafts with the percentages given in the table. Suppose a shaft is selected at random from the 12,246 currently in stock, and the warehouse number and type of shaft are observed. Given that the shaft is produced in warehouse 2, find the probability it has an extra stiff shaft. A) 0.419 B) 0.351 C) 0.37 D) 0.684

Assume that blood pressure readings are normally distributed with a mean of 117 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 119. A) 0.9938 B) 0.9998 C) 0.8615 D) 0.0062

Construct a 95% confidence interval for p1 - p2. The sample statistics listed below are from independent samples. Sample statistics: n1 = 50, x1 = 35, and n2 = 60, x2 = 40 A) (-0.141, 0.208) B) (-2.391, 3.112) C) (-1.341, 1.781) D) (-0.871, 0.872)

Construct a 95% confidence interval for μ1 - μ2. Two samples are randomly selected from normal populations. The sample statistics are given below. n1 = 10 n2 = 12 x1 = 25 x2 = 23 s1 = 1.5 s2 = 1.9 A) (0.360, 3.640) B) (1.413, 3.124) C) (1.554, 3.651) D) (1.335, 3.012)

Construct a 98% confidence interval for the population mean, μ. Assume the population has a normal distribution. A study of 14 car owners showed that their average repair bill was $192 with a standard deviation of $8. Round to the nearest cent. A) ($186.33, $197.67) B) ($115.40, $158.80) C) ($222.33, $256.10) D) ($328.33, $386.99)

Find the standardized test statistic, z, to test the hypothesis that p1 ≠ p2. Use α = 0.02. The sample statistics listed below are from independent samples. Sample statistics: n1 = 1000, x1 = 250, and n2 = 1200, x2 = 195 A) 5.087 B) 3.212 C) 4.761 D) 2.798

Find the test statistic, t, to test the hypothesis that μ1 = μ2. Two samples are randomly selected and come from populations that are normal. The sample statistics are given below. n1 = 14 n2 = 12 x1 = 18 x2 = 19 s1 = 2.5 s2 = 2.8 A) -0.954 B) -0.909 C) -0.915 D) -1.558

Find the z-score for which the area under the standard normal curve to its left is 0.96 A) 1.75 B) -1.38 C) 1.82 D) 1.03

In order for a company's employees to work for the foreign office, they must take a test in the language of the country where they plan to work. The data below show the relationship between the number of years that employees have studied a particular language and the grades they received on the proficiency exam. What is the best predicted value for y given x = 3.5? A) 70 B) 66 C) 72 D) 68

Mark retired from competitive athletics last year. In his career as a sprinter he had competed in the 100-meters event a total of 328 times. His average time for these 328 races was 10.23 seconds. A) parameter B) statistic

Suppose a brewery has a filling machine that fills 12-ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.23 ounces and a standard deviation of 0.04 ounce. The company is interested in reducing the amount of extra beer that is poured into the 12 ounce bottles. The company is seeking to identify the highest 1.5% of the fill amounts poured by this machine. For what fill amount are they searching? Round to the nearest thousandth. A) 12.317 oz B) 12.087 oz C) 12.143 oz D) 11.913 oz

Suppose you want to test the claim that μ ≠ 3.5. Given a sample size of n = 48 and a level of significance of α = 0.05, when should you reject H0 ? A) Reject H0 if the standardized test statistic is greater than 1.96 or less than -1.96. B) Reject H0 if the standardized test statistic is greater than 1.645 or less than -1.645 C) Reject H0 if the standardized test statistic is greater than 2.575 or less than -2.575. D) Reject H0 if the standardized test statistic is greater than 2.33 or less than -2.33

A farmer wishes to test the effects of a new fertilizer on her wheat yield. She has four equal-sized plots of land-- one with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal-sized portions and randomly labels them A, B, and C. The four A portions of land are treated with her old fertilizer. The four B portions are treated with the new fertilizer, and the four C's are treated with no fertilizer. At harvest time, the wheat yield is recorded for each section of land. How many levels does the treatment have in this experiment? A) 1 (wheat yield) B) 12 (sections of land) C) 3 (old, new, or no fertilizer) D) 4 (rocky, sandy, clay, or average soil)

The random variable x represents the number of computers that families have along with the corresponding probabilities. Find the mean and standard deviation for the random variable x. x P(x) 0 0.49 1 0.05 2 0.32 3 0.07 4 0.07 A) mean: 1.18; standard deviation: 1.30 B) mean: 1.39; standard deviation: 0.64 C) mean: 1.18; standard deviation: 0.64 D) mean: 1.39; standard deviation: 0.80

The table lists the drinking habits of a group of college students. If a student is chosen at random, find the probability of getting someone who is a non-drinker. Round your answer to three decimal places A) 0.770 B) 0.919 C) 0.230 D) 1

The weights (in pounds) of babies born at St Mary's hospital last month are summarized in the table. Weight (lb) Number of Babies 5.0 - 5.8 8 5.9 - 6.7 18 6.8 - 7.6 20 7.7 - 8.5 9 8.6 - 9.4 4 Find the class width. A) 0.9 lb B) 0.8 lb C) 0.85 lb D) 0.95 lb

True or False: Every Student's t-distribution with n < N, n the number in the sample and N the number in the population, will be less peaked and have thinner tails. A) False B) True

True or False: If I specify β to be equal to 0.35, then the value of α must be 0.65. A) False B) True

True or False: In a uniform probability distribution, any random variable is just as likely as any other random variable to occur, provided the random variables belong to the distribution. A) True B) False

True or False: The proportion of the population that has certain characteristics is the same as the probability that a randomly selected individual of the population has these same characteristics. A) True B) False

Use the regression equation to predict the value of y for x = -3.5. A) 7.356 B) -0.768 C) -4.538 D) -5.839

You are dealt one card from a standard 52-card deck. Find the probability of being dealt a picture card. A) 3/13 B) 3/52 C) 3/26 D) 1/13

You roll two dice and total the up faces. What is the probability of getting a total of 8 or two up faces that are the same? Round the the nearest hundredth. A) 0.28 B) 0.50 C) 0.31 D) 0.33

category of storm (gale, hurricane, etc.) A) ordinal B) interval C) nominal D) ratio

he percentage of measurements that are above the 39th percentile is A) 61% B) cannot determine C) 39% D) 71%

the age of the oldest employee in the data processing department A) continuous B) discrete

the cholesterol levels of a group of adults the day after Thanksgiving A) continuous B) discrete

the number of phone calls to the police department on any given day A) discrete B) continuous

A medical researcher wishes to determine if there is a relationship between the number of prescriptions written by pediatricians and the ages of the children for whom the prescriptions are written. She surveys all the pediatricians in a geographical region to collect her data. What is the response variable? A) Pediatricians surveyed B) Number of prescriptions written C) Number of children for whom prescriptions were written D) Age of the children for whom prescriptions were written

A national caterer determined that 87% of the people who sampled their food said that it was delicious. A random sample of 144 people is obtained from a population of 5000. The 144 people are asked to sample the caterer's food. If p ^ is the sample proportion saying that the food is delicious, what is the mean of the sampling distribution of p ^ ? A) 0.42 B) 0.87 C) 1.25 D) 0.19

A quiz consists of 10 multiple choice questions, each with five possible answers, one of which is correct. To pass the quiz a student must get 60% or better on the quiz. If a student randomly guesses, what is the probability that the student will pass the quiz? A) 0.205 B) 0.006 C) 0.377 D) 0.060

A random sample of 100 students at a high school was asked whether they would ask their father or mother for help with a financial problem. A second sample of 100 different students was asked the same question regarding a dating problem. Forty-three students in the first sample and 47 students in the second sample replied that they turned to their mother rather than their father for help. Construct a 98% confidence interval for p1 - p2. A) (-1.324, 1.521) B) (-0.204, 0.124) C) (-0.591, 0.762) D) (-1.113, 1.311)

A recent survey found that 70% of all adults over 50 wear sunglasses for driving. In a random sample of 10 adults over 50, what is the probability that at least six wear sunglasses? A) 0.006 B) 0.850 C) 0.200 D) 0.700

A researcher records the number of employees of each of the IT companies in the town of Westmoore. The results are summarized in the table. Number of Employees Number of IT Companies 0 - 399 32 400 - 799 21 800 - 1199 5 1200 - 1599 10 1600 - 1999 10 Find the class limits of the third class. A) lower limit: 799; upper limit: 1200 B) lower limit: 800; upper limit: 1199 C) lower limit: 800; upper limit: 1200 D) lower limit: 799.5; upper limit: 1199.5

Compute the sum of the squared residuals of the least-squares line for the given data. A) 1.036 B) 7.624 C) 0 D) 2.097

Construct a 98% confidence interval for p1 - p2. The sample statistics listed below are from independent samples. Sample statistics: n1 = 1000, x1 = 250, and n2 = 1200, x2 = 195 A) (0.581, 1.819) B) (0.047, 0.128) C) (1.516, 3.021) D) (-0.621, 0.781)

Determine the critical value zα/2 that corresponds to the given level of confidence. 97% A) 1.88 B) 2.17 C) 0.83 D) 1.92

Determine the critical values for a two-tailed test of a population mean at the α = 0.1 level of significance based on a sample size of n = 8. A) ±1.397 B) ±1.895 C) ±1.415 D) ±1.86

Determine the number of classes in the frequency table below. Class Frequency 23-24 7 25-26 2 27-28 6 29-30 4 31-32 1 A) 2 B) 5 C) 20 D) 6

Determine the sample size required to estimate the mean score on a standardized test within 4 points of the true mean with 99% confidence. Assume that s = 15 based on earlier studies. A) 194 B) 94 C) 1 D) 10

Find the standardized test statistic t for a sample with n = 15, x = 4.9, s = 0.8, and α = 0.05 if H0: μ ≤ 4.6. Round your answer to three decimal places. A) 1.312 B) 1.452 C) 1.728 D) 1.631

If the individuals selected for a sample have no influence upon which individuals are selected for a second sample, then the samples are said to be A) consistent B) independent C) dependent D) inconsistent

In a survey conducted in the town of Atherton, 29% of adult respondents reported that they had been involved in at least one car accident in the past ten years. A) parameter B) statistic

In distributions that are skewed to the right, what is the relationship of the mean, median, and mode? A) mode > median > mean B) mean > median > mode C) mode > mean > median D) median > mean > mode

One year, professional sports players salaries averaged $1.9 million with a standard deviation of $0.9 million. Suppose a sample of 400 major league players was taken. Find the approximate probability that the average salary of the 400 players exceeded $1.1 million. A) approximately 0 B) approximately 1 C) 0.2357 D) 0.7357

The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered investment properties. If a sample of 800 homes sold in 2004 is obtained and it was noted that 248 homes were to be used as investment property, would this be unusual? Answer Yes or No A) No B) Yes

The ages of five randomly chosen cars in a parking garage are determined to be 7, 9, 3, 4, and 6 years old. If we consider this sample of 5 in groups of 3, what is the probability of the population mean falling between 5.5 and 6.5 years? A) 0.55 B) 0.5 C) 0.6 D) 0.4

The annual profits of five large corporations in a certain area are given below. Which measure of central tendency should be used? $209,000 $217,000 $237,000 $207,000 $1,287,000 A) midrange B) median C) mean D) mode

The data below are the temperatures on randomly chosen days during the summer in one city and the number of employee absences on those days for a company located in the same city. What is the best predicted value for y given x = 74? A) 5 B) 3 C) 6 D) 4

The following Venn diagram is for the six sample points possible when rolling a fair die. Let A be the event rolling an even number and let B be the event rolling a number greater than 1. Which of the following events describes the event rolling a 1? A) Ac B) Bc C) A ∪ B D) B

The following data represent the living situation of newlyweds in a large metropolitan area and their annual household income. What percent of people who make between $20,000 and $35,000 per year own their own home? Round to the nearest tenth of a percent A) 4.5% B) 27.8% C) 36.9% D) 35.3%

The following is a sample of 19 November utility bills (in dollars) from a neighborhood.What is the largest bill in the sample that would not be considered an outlier? 52, 62, 66, 68, 72, 74, 76, 76, 76, 78, 78, 82, 84, 84, 86, 88, 92, 96, 110 A) $86 B) $96 C) $95 D) $88

The mean age of principals in a local school district is 48.6 years. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is not sufficient evidence to reject the claim μ = 48.6. B) There is sufficient evidence to reject the claim μ = 48.6. C) There is sufficient evidence to support the claim μ = 48.6. D) There is not sufficient evidence to support the claim μ = 48.6.

The mean monthly gasoline bill for one household is greater than $140. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis? A) There is sufficient evidence to reject the claim μ > $140. B) There is not sufficient evidence to support the claim μ > $140. C) There is not sufficient evidence to reject the claim μ > $140. D) There is sufficient evidence to support the claim μ > $140.

The normal density curve is symmetric about A) An inflection point B) Its mean C) The horizontal axis D) A point located one standard deviation from the mean

The probability that an individual has 20-20 vision is 0.13. In a class of 90 students, what is the mean and standard deviation of the number with 20-20 vision in the class? A) mean: 90; standard deviation: 3.19045451 B) mean: 11.7; standard deviation: 3.19045451 C) mean: 90; standard deviation: 3.42052628 D) mean: 11.7; standard deviation: 3.42052628

The regression line for the given data is y = -1.885x + 0.758. Determine the residual of a data point for which x = 2 and y = -4. A) -3.012 B) -0.988 C) -7.012 D) -6.298

The repair costs for five cars which were crashed by a safety testing organization were as follows: $100, $150, $200, $250, and $150. Find the mean cost of repair. A) $160 B) $170 C) $180 D) $140

the number of seats in a school auditorium A) qualitative B) quantitative

High temperatures in a certain city for the month of August follow a uniform distribution over the interval 69°F to 99°F. Find the high temperature which 90% of the August days exceed. A) 96°F B) 72°F C) 79°F D) 99°F

B) To find: T= 69 + (1-0.9) x (99-69) T+ 69+ 0.1 x 30 = 72

A computer package was used to generate the following printout for estimating the sale price of condominiums in a particular neighborhood. X = sale_price SAMPLE MEAN OF X = 46,500 SAMPLE STANDARD DEV = 13,747 SAMPLE SIZE OF X = 15 CONFIDENCE = 95 UPPER LIMIT = 54,113.60 SAMPLE MEAN OF X = 46,500 LOWER LIMIT = 38,886.40 What assumptions are necessary for any inferences derived from this printout to be valid? A) The population mean has an approximate normal distribution. B) The sample variance equals the population variance. C) The sample was randomly selected from an approximately normal population. D) All of these are necessary

A drug company wanted to test a new indigestion medication. The researchers found 400 adults aged 25-35 and randomly assigned them to two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose indigestion symptoms decreased was recorded and compared. What is the treatment in this experiment? A) the percentage who had decreased indigestion symptoms B) the 400 adults aged 25-35 C) the drug D) the one month treatment time

A fair coin is tossed two times in succession. The set of equally likely outcomes is {HH, HT, TH, TT}. Find the probability of getting the same outcome on each toss. A) 1 B) 3/4 C) 1/2 D) 1/4

A survey of 2690 musicians showed that 361 of them are left-handed. Find a point estimate for p, the population proportion of musicians that are left-handed. A) 0.118 B) 0.155 C) 0.866 D) 0.134

Construct a 95% confidence interval for μ1 - μ2. Two samples are randomly selected from normal populations. The sample statistics are given below. n1 = 8 n2 = 7 x1 = 4.1 x2 = 5.5 s1 = 0.76 s2 = 2.51 A) (-3.813, 1.013) B) (-1.132, 1.543) C) (2.112, 2.113) D) (-1.679, 1.987)

Determine the area under the standard normal curve that lies between: z = -2 and z = -0.3 A) 0.0228 B) 0.3821 C) 0.6179 D) 0.3593

Find the area under the standard normal curve between z = -1.5 and z = 2.5. A) 0.7182 B) 0.6312 C) 0.9831 D) 0.9270

Find the z-score for which the area under the standard normal curve to its left is 0.40 A) 0.57 B) -0.57 C) 0.25 D) -0.25

Suppose x is a uniform random variable with c = 20 and d = 70. Find the probability that a randomly selected observation is between 23 and 65. A) 0.8 B) 0.16 C) 0.5 D) 0.84

D) To find: 70-65 70-23 ------- - ------ =0.84 70-20 70-20

Smith is a weld inspector at a shipyard. He knows from keeping track of good and substandard welds that for the afternoon shift 5% of all welds done will be substandard. If Smith checks 300 of the 7500 welds completed that shift, what is the probability that he will find between 10 and 20 substandard welds? A) 0.2033 B) 0.6377 C) 0.4066 D) 0.8132

A random sample of sale prices of homes yielded the following summary information: MIN $46,000 25%: $81,000 Median: $136,000 MAX $272,000 75%: $164,000 Comment on a home that had a sale price of $411,000. A) This sale price would be expected since it falls inside the lower and upper fences. B) This sale price falls between the lower and upper fences. It can be considered a potential outlier. C) This value falls outside the upper fence and is considered an outlier. D) This value falls outside of the third quartile, but cannot be considered an outlier.

A residual is the difference between A) the observed value of y and the predicted value of x. B) the observed value of x and the predicted value of y. C) the observed value of y and the predicted value of y. D) the observed value of x and the predicted value of x.

A statistics student interviews everyone in his apartment building to determine who owns a cell phone. What sampling technique is used? A) cluster B) simple random C) convenience D) stratified E) systematic

A student is asked to rate a guest speaker's ability to communicate on a scale of poor-average-good-excellent. The student is to fill in a corresponding circle on a bubble form. This is an example of collecting what type of data? A) continuous B) insightful C) qualitative D) discrete

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Use a 99% confidence interval to estimate the true proportion of students on financial aid. Express the answer in the form p ^± E and round to the nearest thousandth. A) 0.59 ± 0.623 B) 0.59 ± 0.007 C) 0.59 ± 0.090 D) 0.59 ± 0.003

According to insurance records a car with a certain protection system will be recovered 94% of the time. Find the probability that 3 of 6 stolen cars will be recovered. A) 0.94 B) 0.06 C) 0.004 D) 0.500

Assume that male and female births are equally likely and that the birth of any child does not affect the probability of the gender of any other children. Find the probability of exactly five girls in ten births. A) 7.875 B) 0.05 C) 0.246 D) 0.5

Consider the discrete probability distribution to the right when answering the following question. Find the probability that x exceeds 5 A) 0.78 B) 0.27 C) 0.51 D) 0.49

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph cannot represent a normal density function because it is bimodal. B) The graph can represent a normal density function. C) The graph cannot represent a normal density function because it is not symmetric. D) The graph cannot represent a normal density function because as x increases without bound, the graph takes negative values

Determine whether the graph can represent a normal curve. If it cannot, explain why A) The graph cannot represent a normal density function because it is not symmetric. B) The graph cannot represent a normal density function because the area under the graph is less than 1. C) The graph cannot represent a normal density function because the graph takes negative values for some values of x. D) The graph can represent a normal density function.

Find the area under the standard normal curve to the right of z = 1. A) 0.8413 B) 0.5398 C) 0.1587 D) 0.1397

Find the critical t-value that corresponds to 90% confidence and n = 15. A) 2.624 B) 1.345 C) 1.761 D) 2.145

Find the equation of the regression line for the given data. Round values to the nearest thousandth. A) y= -2.097x + 0.206 B) y= 0.206x - 2.097 C) y= -0.206x + 2.097 D)y= 2.097x - 0.206

Find the equation of the regression line for the given data. Round values to the nearest thousandth. A) y= 1.885x - 0.758 B) y= 0.758x + 1.885 C) y= -1.885x + 0.758 D) y= -0.758x - 1.885

Find the standardized test statistic estimate, z, to test the hypothesis that p1 > p2. Use α = 0.01. The sample statistics listed below are from independent samples. Sample statistics: n1 = 100, x1 = 38, and n2 = 140, x2 = 50 A) 1.324 B) 2.116 C) 0.362 D) 0.638

Find the test statistic, t, to test the hypothesis that μ1 > μ2. Two samples are randomly selected and come from populations that are normal. The sample statistics are given below. n1 = 18 n2 = 13 x1 = 745 x2 = 730 s1 = 40 s2 = 25 A) 2.819 B) 1.865 C) 1.282 D) 3.271

Find the z-score for which the area under the standard normal curve to its right is 0.09. A) 1.39 B) 1.45 C) 1.34 D) 1.26

Find the z-score having area 0.86 to its right under the standard normal curve; that is, find z 0.86 . A) 1.08 B) 0.5557 C) -1.08 D) 0.8051

If one card is drawn from a standard 52 card playing deck, determine the probability of getting a ten, a king or a diamond. Round to the nearest hundredth. A) 0.40 B) 0.31 C) 0.37 D) 0.29

If p is the probability of success of a binomial experiment, then the probability of failure is A) x/n B) n/x C) 1 - p D) -p

In a random sample of 60 dog owners enrolled in obedience training, it was determined that the mean amount of money spent per owner was $109.33 per class. Assuming the population standard deviation of the amount spent per owner is $12, construct and interpret a 95% confidence interval for the mean amount spent per owner for an obedience class. A) ($106.78, $111.88); we are 95% confident that the mean amount spent per dog owner for a single obedience class is between $106.78 and $111.88. B) ($106.23, $112.43); we are 95% confident that the mean amount spent per dog owner for a single obedience class is between $106.23 and $112.43. C) ($106.29, $112.37); we are 95% confident that the mean amount spent per dog owner for a single obedience class is between $106.29 and $112.37. D) ($106.74, $111.92); we are 95% confident that the mean amount spent per dog owner for a single obedience class is between $106.74 and $111.92.

In a recent online survey, participants were asked to answer "yes" or "no" to the question "Are you in favor of stricter gun control?" 6571 responded "yes" while 4537 responded "no". There was a fifty-cent charge for the call. What sampling technique was used? A) simple random B) systematic C) convenience D) stratified

In interpreting a boxplot of a data set we note that the median is to the left of the center of the box and the right line is longer than the left line. We can conclude that A) The data is symmetric. B) The data is skewed left. C) The data is skewed right. D) Skewness or symmetry cannot be determined by a box plot.

In the game of roulette in the United States a wheel has 38 slots: 18 slots are black, 18 slots are red, and 2 slots are green. We watched a friend play roulette for two hours. In that time we noted that the wheel was spun 50 times and that out of those 50 spins black came up 22 times. Based on this data, the P(black ) = 22 50 = 0.44. This is an example of what type of probability? A) Subjective B) Classical C) Empirical D) Observational

Suppose a brewery has a filling machine that fills 12 ounce bottles of beer. It is known that the amount of beer poured by this filling machine follows a normal distribution with a mean of 12.16 ounces and a standard deviation of 0.04 ounce. Find the probability that the bottle contains fewer than 12.06 ounces of beer. A) 0.4938 B) 0.5062 C) 0.0062 D) 0.9938

The breakdown of workers in a particular state according to their political affiliation and type of job held is shown here. Suppose a worker is selected at random within the state and the worker's political affiliation and type of job are noted. Given the worker is a Democrat, what is the probability that the worker is in a white collar job A) 0.423 B) 0.456 C) 0.262 D) 0.193

The business college computing center wants to determine the proportion of business students who have personal computers (PC's) at home. If the proportion differs from 25%, then the lab will modify a proposed enlargement of its facilities. Suppose a hypothesis test is conducted and the test statistic is 2.4. Find the P-value for a two-tailed test of hypothesis. A) 0.0082 B) 0.4836 C) 0.0164 D) 0.4918

The data below are the number of absences and the final grades of 9 randomly selected students from a literature class. Find the equation of the regression line for the given data. What would be the predicted final grade if a student was absent 14 times? Round the regression line values to the nearest hundredth. Round the predicted grade to the nearest whole number. A) y ^ = 96.14x - 2.75; 1343 B) y ^ = -96.14x + 2.75; 1343 C) y ^ = -2.75x + 96.14; 58 D) y ^ = -2.75x - 96.14; 134.64

The mean age of professors at a university is greater than 57.7 years. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is not sufficient evidence to reject the claim μ > 57.7. B) There is sufficient evidence to reject the claim μ > 57.7. C) There is sufficient evidence to support the claim μ > 57.7. D) There is not sufficient evidence to support the claim μ > 57.7.

The owner of a computer repair shop has determined that their daily revenue has mean $7200 and standard deviation $1200. The daily revenue totals for the next 30 days will be monitored. What is the probability that the mean daily revenue for the next 30 days will be between $7000 and $7500? A) 0.8186 B) 0.9147 C) 0.7333 D) 0.2667

The top 38 cities in Wisconsin as determined by population are given below. Select a random sample of four cities from the list below using the two digit list of random numbers provided. Begin with the uppermost left random number and proceed down each column. When a column is complete, use the numbers at the top of the next right column and proceed down that column. Information was obtained from the web site http://www.citypopulation.de/USA-Wisconsin.html. Wisconsin Cities by Population A) Milwaukee, Eau Claire, New Berlin, West Bend. B) Milwaukee, Madison, Green Bay, Kenosha. C) Manitowoc, La Crosse, Franklin, Oshkosh. D) Manitowoc, Appleton, Greenfield, Fond du Lac

The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1100 miles. What warranty should the company use if they want 96% of the tires to outlast the warranty? A) 61,925 mi B) 58,900 mi C) 58,075 mi D) 61,100 mi

What is the H0 for testing differences of the means of two independent samples? A) H0:μ1 ≠ μ2 B) H0:μ1 < μ2 C) H0:μ1 - μ2 = 0 D) H0:μ1 > μ2

What is the probability associated with not making a Type II error? A) (1 - α) B) β C) (1 - β) D) α

Which measure of central tendency may have more than one value in a numeric data set? A) Mean B) Midrange C) Mode D) Median

Which measure of central tendency may not exist for all numeric data sets? A) Midrange B) Median C) Mode D) Mean

Which of the following cannot be the probability of an event? A) 5/3 B) 0 C) -61 D) 0.001

You are dealt one card from a standard 52-card deck. Find the probability of being dealt an ace or a 6. A) 7 B) 13/2 C) 2/13 D) 7/26

x 10 11 16 9 7 15 16 10 y 96 51 62 58 89 81 46 51 A) r = -0.284; no linear relation exists B) r = 0.462; linear relation exists C) r = -0.335; no linear relation exists D) r = -0.335; linear relation exists

z0.05 A) -1.645 B) 1.75 C) 1.645 D) 0.52

The diameter of ball bearings produced in a manufacturing process can be explained using a uniform distribution over the interval 6.5 to 8.5 millimeters. What is the probability that a randomly selected ball bearing has a diameter greater than 7.6 millimeters? A) 0.8941 B) 3.5 C) 0.45 D) 0.5067

C) To Find : 8.5-7.6 -------= 0.45 8.5-6.5

Describe the shape of the distribution. A) bell shaped B) uniform C) skewed to the left D) skewed to the right

C) skewed to the left

Describe the shape of the distribution. A) bell shaped B) skewed to the left C) skewed to the right D) uniform

C) skewed to the right

The dean of a major university claims that the mean number of hours students study at her University (per day) is at most 4.9 hours. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A) There is sufficient evidence to support the claim μ ≤ 4.9. B) There is not sufficient evidence to support the claim μ ≤ 4.9. C) There is not sufficient evidence to reject the claim μ ≤ 4.9. D) There is sufficient evidence to reject the claim μ ≤ 4.9

The distribution of salaries of professional basketball players is skewed to the right. Which measure of central tendency would be the best measure to determine the location of the center of the distribution? A) mode B) mean C) frequency D) median

The legal profession conducted a study to determine the percentage of cardiologists who had been sued for malpractice in the last three years. The sample was randomly chosen from a national directory of doctors. Identify the individuals in the study. A) the responses: have been sued/have not been sued for malpractice in the last three years B) the doctor's area of expertise (i.e., cardiology, pediatrics, etc.) C) all cardiologists in the directory D) each cardiologist selected from the directory

The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 6.5 minutes and a standard deviation of 1 minute. Find the probability that a randomly selected college student will find a parking spot in the library parking lot in less than 6.0 minutes. A) 0.1915 B) 0.2674 C) 0.3551 D) 0.3085

A fast-food restaurant chain with 700 outlets in the United States describes the geographic location of its restaurants with the accompanying table of percentages. A restaurant is to be chosen at random from the 700 to test market a new style of chicken. Given that the restaurant is located in the eastern United States, what is the probability it is located in a city with a population of at least 10,000? A) 0.43 B) 0.483 C) 0.157 D) 0.843

A history instructor has given the same pretest and the same final examination each semester. He is interested in determining if there is a relationship between the scores of the two tests. He computes the linear correlation coefficient and notes that it is 1.15. What does this correlation coefficient value tell the instructor? A) The correlation is something other than linear. B) There is a strong positive correlation between the tests. C) There is a strong negative correlation between the tests. D) The history instructor has made a computational error.

A local outdoor equipment store is being sold. The buyers are trying to estimate the percentage of items that are outdated. They will randomly sample among its 100,000 items in order to determine the proportion of merchandise that is outdated. The current owners have never determined their outdated percentage and can not help the buyers. Approximately how large a sample do the buyers need in order to insure that they are 95% confident that the margin of error is within 5%? A) 1537 B) 769 C) 196 D) 385

A machine is set to pump cleanser into a process at the rate of 9 gallons per minute. Upon inspection, it is learned that the machine actually pumps cleanser at a rate described by the uniform distribution over the interval 8.5 to 11.5 gallons per minute. Find the probability that between 9.0 gallons and 10.0 gallons are pumped during a randomly selected minute. A) 0.67 B) 0 C) 1 D) 0.33

A psychologist wants to measure the effect of music on memory. He randomly selects 80 students and measures their scores on a memory test conducted in silence. The next day he measures their scores on a similar test conducted while classical music is playing. The mean score without music is compared to the mean score with music. A) quantitative, independent B) qualitative, independent C) qualitative, dependent D) quantitative, dependent

A recent study attempted to estimate the proportion of Florida residents who were willing to spend more tax dollars on protecting the Florida beaches from environmental disasters. Thirty-one hundred Florida residents were surveyed. Which of the following is the population used in the study? A) the Florida residents who were willing to spend more tax dollars on protecting the beaches from environmental disasters B) all Florida residents who lived along the beaches C) the 3100 Florida residents surveyed D) all Florida residents

A researcher at a major clinic wishes to estimate the proportion of the adult population of the United States that has sleep deprivation. How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the true proportion by more than 5%? A) 13 B) 543 C) 1327 D) 664

A study was designed to investigate the effects of two variables - (1) a student's level of mathematical anxiety and (2) teaching method - on a student's achievement in a mathematics course. Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 400 with a standard deviation of 40 on a standardized test. Assuming no information concerning the shape of the distribution is known, what percentage of the students scored between 320 and 480? A) approximately 95% B) approximately 68% C) at least 88.9% D) at least 75%

A survey claims that 9 out of 10 doctors (i.e., 90%) recommend brand Z for their patients who have children. To test this claim against the alternative that the actual proportion of doctors who recommend brand Z is less than 90%, a random sample of 100 doctors results in 83 who indicate that they recommend brand Z. The test statistic in this problem is approximately (round to the nearest hundredth): A) -1.99 B) 2.33 C) -1.83 D) -2.33

The owner of a farmer's market was interested in determining how many oranges a person buys when they buy oranges. He asked the cashiers over a weekend to count how many oranges a person bought when they bought oranges and record this number for analysis at a later time. The data is given below in the table. The random variable x represents the number of oranges purchased and P(x) represents the probability that a customer will buy x oranges. Determine the variance of the number of oranges purchased by a customer. A) 0.56 B) 1.95 C) 3.97 D) 3.57

The percentage of measurements that are below the 88th percentile is A) 12% B) 22% C) cannot determine D) 88%

The probability that a football game will go into overtime is 17%. What is the probability that two of three football games will go to into overtime? A) 0.0289 B) 0.17 C) 0.351 D) 0.072

The probability that an individual has 20-20 vision is 0.13. In a class of 16 students, what is the probability of finding five people with 20-20 vision? A) 0.313 B) 0.000 C) 0.13 D) 0.035

The regression line for the given data is y ^ = 0.449x - 30.27. Determine the residual of a data point for which x = 75 and y = 4. A) 7.405 B) 3.405 C) 103.474 D) 0.595

Determine μ x and σ x from the given parameters of the population and the sample size. Round the answer to the nearest thousandth where appropriate. 1) μ = 25, σ = 12, n = 16 A) μx = 25, σx = 12 B) μx = 6.25, σx = 3 C) μx = 25, σx = 0.75 D) μx = 25, σx = 3

Find the test statistic to test the hypothesis that μ1 = μ2. Two samples are randomly selected from each population. The sample statistics are given below. Use α = 0.05. n1 = 40 n2 = 35 x1 = 19 x2 = 20 s1 = 2.5 s2 = 2.8 A) -1.0 B) -2.6 C) -0.8 D) -1.6

Find the test statistic to test the hypothesis that μ1 > μ2. Two samples are randomly selected from each population. The sample statistics are given below. Use α = 0.05. n1 = 100 n2 = 125 x1 = 585 x2 = 570 s1 = 45 s2 = 25 A) 1.86 B) 2.81 C) 0.91 D) 2.98

Find the test statistic, t, to test the hypothesis that μ1 ≠ μ2. Two samples are randomly selected and come from populations that are normal. The sample statistics are given below. n1 = 11 n2 = 18 x1 = 7.4 x2 = 7.8 s1 = 0.76 s2 = 0.51 A) -1.821 B) -2.123 C) -1.326 D) -1.546

Find the z-score for which the area under the standard normal curve to its left is 0.70. A) 0.47 B) 0.98 C) 0.81 D) 0.53

For the distribution drawn here, identify the mean, median, and mode. A) A = mode, B = mean, C = median B) A = mean, B = mode, C = median C) A = median, B = mode,C = mean D) A = mode, B = median, C = mean

Given the equation of a regression line is y= -4.5x- 2.4, what is the best predicted value for y given x = 2.3? A) 7.95 B) -7.95 C) 12.75 D) -12.75

The table lists the drinking habits of a group of college students. If a student is chosen at random, find the probability of getting someone who is a regular or heavy drinker. Round your answer to three decimal places. Sex Non-drinker Regular Drinker Heavy Drinker Total Man 135 55 5 195 Woman 187 21 9 217 Total 322 76 14 412 A) 0.711 B) 0.155 C) 0.259 D) 0.218

The table lists the drinking habits of a group of college students. If a student is chosen at random, find the probability of getting someone who is a woman or a heavy drinker. Round your answer to three decimal places A) 0.191 B) 0.921 C) 0.791 D) 0.526

The weights (in ounces) of a sample of tomatoes of a particular variety are summarized in the boxplot below. Based on the boxplot, is a large sample necessary to conduct a hypothesis test about the mean weight? If so, why? A) Yes; data do not appear to be normally distributed but skewed left. B) No; data appear to be normally distributed with no outliers. C) Yes; data do not appear to be normally distributed but skewed right. D) Yes; data contain outliers.

Use the graph to approximate the test score that corresponds to the 50th percentile? A) 20 B) 25 C) 62 D) 68

If we have a sample of 12 drawn from a normal population, then we would use as our test statistic A) z0 with 12 degrees of freedom B) z0 with 11 degrees of freedom C) t0 with 12 degrees of freedom D) t0 with 11 degrees of freedom

In a college student poll, it is of interest to estimate the proportion p of students in favor of changing from a quarter-system to a semester-system. How many students should be polled so that we can estimate p to within 0.09 using a 99% confidence interval? A) 114 B) 182 C) 261 D) 205

What are the values of μx and σx for the sampling distribution of the sample mean shown? 9.95 10 10.05 A) μx = 10, σx = 0.1 B) μx = 0.05, σx = 10 C) μx = 10, σx = 0.15 D) μx = 10, σx = 0.05

When forming a confidence interval for matched-pair data the point estimate is the A) standard deviation of the differences. B) differences of the standard deviations. C) difference of the means. D) mean of the differences.

When the effects of the explanatory variable upon the response variable cannot be determined, then A) a lurking variable is present. B) there is sampling error. C) the claim is invalid. D) confounding has occurred.

Determine the Null and Alternative Hypotheses CAUTION

If population data are available, there is no need for inferential statistics

A point estimate is the value of a statistic that estimates the value of a

parameter

Random sampling is the process of using chance to

select individuals from a population to be included in the sample -If convenience is used to obtain a sample, the results of the survey are meaningless

The variance of a variable is the square of the

standard deviation. The population variance is σ2 and the sample variance is s2

The z-score represents

the distance that a data value is from the mean in terms of the number of standard deviations. We find it by subtracting the mean from the data value and dividing this result by the standard deviation

Skewed left

the tail to the left of the peak is longer than the tailto the right of the pea

Skewed right

the tail to the right of the peak is longer than the tail to the left of the peak

The Empirical Rule

•Approximately 68% of the data will lie within 1 standard deviation of the mean. That is, approximately 68% of the data lie between μ− 1σ and μ + 1σ. •Approximately 95% of the data will lie within 2 standard deviations of the mean. That is, approximately 95% of the data lie between μ − 2σ and μ + 2σ. •Approximately 99.7% of the data will lie within 3 standard deviations of the mean. That is, approximately 99.7% of the data lie between μ− 3σ and μ + 3σ

Confidence interval estimates for the population proportion are of the form

The margin of error of a confidence interval estimate of a parameter is a measure of how accurate the point estimate

Central Limit Theorem

The theory that, as sample size increases, the distribution of sample means of size n, randomly selected, approaches a normal distribution.

A market researcher randomly selects 100 homeowners under 55 years of age and 100 homeowners over 55 years of age. What sampling technique was used? A) systematic B) cluster C) convenience D) simple random E) stratified

Explain the Various Types of Observational Studies

(1) cross-sectional studies, (2) case-control studies (3) cohort studies.

the number of pills in an aspirin bottle A) discrete B) continuous

height of a tree A) ordinal B) nominal C) ratio D) interval C) ratio

Use the linear correlation coefficient given to determine the coefficient of determination, R2. r = 0.89 A) R2 = 94.34% B) R2 = 9.43% C) R2 = 7.921% D) R2 = 79.21%

2 Construct and interpret a confidence interval for the population proportion.

/ ------------- P +/- x Za/2 x / P x (1-P) / n

25.2% of the mayors of cities in a certain state are from minority groups. A) parameter B) statistic

72) An event is considered unusual if the probability of observing the event is A) less than 0.05 B) greater than 0.95 C) less than 0.025 D) less than 0.10

A pollster obtains a sample of students and asks them how they will vote on an upcoming referendum. A) observational study B) experiment

Find the standardized test statistic, z, to test the hypothesis that p1 < p2. Use α = 0.10. The sample statistics listed below are from independent samples. Sample statistics: n1 = 550, x1 = 121, and n2 = 690, x2 = 195 A) -2.513 B) -2.132 C) 1.116 D) -0.985

Suppose that E and F are two events and that P(E) = 0.2 and P(F E) = 0.3. What is P(E and F)? A) 0.06 B) 0.006 C) 0.5 D) 0.667

The payroll amounts for 26 major-league baseball teams are shown below. Aprroximately what percentage of the payrolls were in the $30-$40 million range? Round to the nearest whole percent. A) 31% B) 8% C) 19% D) 42%

A baseball player is asked to swing at pitches in sets of four. The player swings at 100 sets of 4 pitches. The probability distribution for making a particular number of hits is given below. Determine the mean for this discrete probability distribution. A) 4 B) 3 C) 2 D) 3.5

The coefficient of correlation between x and y is r = 0.59. Calculate the coefficient of determination R2. Round R2 to the nearest hundredth. A) 0.65 B) 0.35 C) 0.41 D) 0.59

True or False: As the level of confidence increases the number of item to be included in a sample will decrease when the error and the standard deviation are held constant. A) True B) False

Use the graph to approximate the percentile rank of an individual whose test score is 50. A) 68 B) 20 C) 25 D) 63

) Find the standardized test statistic t for a sample with n = 20, x = 10.9, s = 2.0, and α = 0.05 if H1: μ < 11.3. Round your answer to three decimal places. A) -1.233 B) -1.265 C) -0.894 D) -0.872

A confidence interval for p can be constructed using A) p ± zα/2 p(1 - p) A) p ± zα/2 p(1 - p) n B) p ^ ± z σ n C) p ^ ± zα/2 p ^ (1 - p ^ ) n D) p ± z σ n

Determine the critical value for a left-tailed test of a population mean at the α = 0.05 level of significance based on a sample size of n = 35. A) 1.690 B) -2.728 C) -1.691 D) 1.691

x -7 -5 2 -1 -3 -4 -2 0 1 -6 y 20 15 3 8 12 13 10 5 4 17 A) r = -0.885; linear relation exists B) r = -0.995; no linear relation exists C) r = -0.995; linear relation exists D) r = -0.885; no linear relation exists

A calculus instructor is interested the performance of his students from Calculus I that go on to Calculus II. Their final grades in each course (in percent) are given below. Compute the sum of the squared residuals of the least squared line for the given data A) 1075.9 B) 11.41 C) 30.85 D) 130.14

A quiz consists of 60 multiple choice questions, each with five possible answers, only one of which is correct. If a student guesses on each question, what is the mean and standard deviation of the number of correct answers? A) mean: 12; standard deviation: 3.46410162 B) mean: 30; standard deviation: 5.47722558 C) mean: 30; standard deviation: 3.09838668 D) mean: 12; standard deviation: 3.09838668

An Excel printout of some descriptive statistics for a set of data is shown below. What is the IQR? A) 15 B) 38 C) 5.5 D) 15.5

If a population proportion is believed to be 0.6, how many items must be sampled to ensure that the sampling distribution of p ^ will be approximately normal? Assume that the size of the population is N = 10,000. A) 13 B) 60 C) 30 D) 42

Find percentage from chart or graph frequency

Total of frequencies in graph wanted frequency percentage over total of all frequencies

Problem Determine whether the following variables are qualitative or quantitative. (a) Gender (b) Temperature (c) Number of days during the past week that a college student studied (d) Zip code

a. qualitative quantitative quantitative qualitative

null hypothesis

denoted H0, is a statement to be tested. The null hypothesis is a statement of no change, no effect, or no difference and is assumed true until evidence indicates otherwise

The classical method of computing probabilities requires

equally likely outcomes. An experiment is said to have equally likely outcomes when each simple event has the same probability of occurring

The interquartile range, IQR, is the range of the

middle 50% of the observations in a data set. That is, the IQR is the difference between the third and first quartiles and is found using the formula

The five-number summary of a set of data consists of the smallest data value, Q1, the median, Q3, and the largest data value. We organize the five-number summary as follow

min Q1 med Q3 max

double-blind experiment is one in which

neither the experimental unit nor the researcher in contact with the experimental unit knows which treatment the experimental unit is receiving.

least squares regression line

the line that makes the sum of the squared residuals as small as possible

A random sample of n1 = 40 individuals results in x1 = 30 successes. An independent sample of n2 = 40 individuals results in x2 = 28 successes. Does this represent sufficient evidence to conclude that p1 > p2 at the α = 0.01 level of significance?

Answer: H0: p1 = p2 vs H1: p1 > p2 z0 = 0.5 < z0.01= 2.33 Do not reject H0 There is not sufficient evidence at the α = 0.01 level of significance to conclude that p1 > p2.

1) H 0 : μ = 9.0 H 1 : μ ≠ 9.0 A) Two-tailed, x B) Two-tailed,μ C) Right-tailed, μ D) Left-tailed, x

51.3% of the residents of Idlington Garden City are female. A) statistic B) parameter

Checking for Outliers by Using Quartiles

Step 1 Determine the first and third quartiles of the data. Step 2 Compute the interquartile range. Step 3 Determine the fences. Fences serve as cutoff points for determining outliers. Lower Fence = Q1− 1.5(IQR) Upper Fence = Q3 + 1.5(IQR) Step 4 If a data value is less than the lower fence or greater than the upper fence, it is considered an outliner

Drawing a boxplot

Step 1 Determine the lower and upper fences.Lower Fence = Q1− 1.5(IQR)Upper Fence = Q3 + 1.5(IQR)where IQR = Q3−Q1 Step 2 Draw a number line long enough to include the maximum and minimum values. Insert vertical lines at Q1, M, and Q3. Enclose these vertical lines in a box. Step 3 Label the lower and upper fence Step 4 Draw a line from Q1 to the smallest data value that is larger than the lower fence. Draw a line from Q3 to the largest data value that is smaller than the upper fence. These lines are called whiskers. Step 5 Any data values less than the lower fence or greater than the upper fence are outliers and are marked with an asterisk

interpretation of the Mean of a Discrete Random Variable

Suppose an experiment is repeated n independent times and the value of the random variable X is recorded. As the number of repetitions of the experiment increases, the mean value of the n trials will approach μX, the mean of the random variable X. In other words, let x1 be the value of the random variable X after the first experiment, x2 be the value of the random variable X after the second experiment, and so on. Then

EXAMPLE Computing Probabilities Using the Classical Method Suppose a "fun size" bag of M&Ms contains 9 brown candies, 6 yellow candies, 7 red candies, 4 orange candies, 2 blue candies, and 2 green candies. Suppose that a candy is randomly selected. (a) What is the probability that it is yellow? (b) What is the probability that it is blue? (c) Comment on the likelihood of the candy being yellow versus bl

a. 0.2 b.0.06 c. yellow, has a greater chance

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