Statistics Mid Term
Determine the smallest weekly earnings of a child that is considered an outlier. NO ANSWER CHOICES
$5.00
In a carnival game, a person can win a prize by guessing which one of 5 identical boxes contains the prize. After each guess, if the prize has been won, a new prize is randomly placed in one of the 5 boxes. If a person makes 4 guesses, what is the probability that the person wins a prize exactly twice?
(4 choose 2) (.2)^2 (.8)^8
A manufacturer makes lightbulbs and claims that their reliability is 98 percent. Reliability is defined to be the proportion of nondefective items that are produced over the long term. If the company's claim is correct, what is the expected number of nondefective lightbulbs in a random sample of 1,000 bulbs? A) 20 B) 200 C) 960 D) 980 E) 1,000
980
A certain type of remote-control car has a fully charged battery at the time of purchase. The distribution of running times of cars of this type, before they require recharging of the battery for the first time after its period of initial use, is approximately normal with a mean of 80 minutes and a standard deviation of 2.5 minutes. A) The probability that the running time of a random selected car of this type, ... , is between 75 minutes and 85 minutes B) The probability that the running time of a random selected car of this type, ... , is between 75 minutes and 82.5 minutes C) The probability that the running time of a random selected car of this type, ... , is between 77.5 minutes and 82.5 minutes D) The probability that the running time of a random selected car of this type, ... , is between 77.5 minutes and 85 minutes E) D) The probability that the running time of a random selected car of this type, ... , is between 77.5 minutes and 87.5 minutes
A
A local real estate magazine used the median instead of the mean when it reported the SAT score of the average student who attends NBHS. A graphical display of SAT scores of students who attend Groveland High School indicated that the data were strongly skewed to the right. Which of the following explains why, in this situation, the median is a more accurate indicator of the SAT score of the average student than the mean is? A) The mean is affected by the skewness, whereas the median is not B) The median is always the preferred statistic C) The mean will be less than the median when the data are strongly skewed to the right D) The means should be used only when the data are strongly skewed to the left. E) The median is equal to one half the sum of the maximum and minimum SAT scores at NBHS.
A
Reggie Richman has a poor driving record and must take out a special insurance policy. He wants to insure his $58,000 sports car. Based on previous driving records, AnyState has estimated the probability of various levels of loss per year as indicated in the table below. x= dollar amount of loss. The company will pay no benefits for any other partial losses. % LOST FROM CAR WRECK X: P(X) 58,000: 0.05 29,000: 0.12 14,500: 0.28 5,800: 0.42 0: 0.13 How much should AnyState charge Reggie for insurance if it wants to make a profit of $1,000 on his policy? A. $13,876.00 B. $12,876.00 C. $11,876.00 D. $1,022.20 E. $22.20
A
Researchers are trying to estimate the amount of exercise that US residents get each week. They randomly sample 1,000 patrons at Gold's Gyms around the nation and ask each one to fill out an anonymous questionnaire. What is the major problem with this study? A. Sampling bias- the sample is likely not representative of the population B. Measurement bias- a questionnaire won't accurately measure amount of exercise C. Non-response bias- most people would refuse to answer the questionnaire D. Hidden bias- the people handing out the questionnaires probably made the patrons want to give different answers E. There is no major problem with this study
A
Suppose A and B are events with the given probabilities. P(A) = .62, P(B) = .44 and P(A^B) = .31 = .31. Which of the following conclusions can be drawn from the data? A) P(A or B) = .75 B) A and B are mutually exclusive events C) A and B are independent events. D) P(A|B) cannot be determined from the given information
A
Suppose that the distribution of a set of scores has a mean of 47 and a standard deviation of 14. If 4 is added to each score, what will be the mean and the standard deviation (respectively) of the distribution of new scores? A. 51 and 14 B. 51 and 18 C. 47 and 14 D. 47 and 16 E. 47 and 18
A
The figure below shows a cumulative relative frequency histogram of 40 scores on a test given in an AP Statistics Class. Which of the following conclusions can be made from the graph? (graph is cumulative percent, range of 30 to 100. ) A. There is greater variability in the lower 20 test scores than in the higher 20 test scores. B. The median test score is less than 50. C. Sixty percent of the students had test scores above 80 D. If the passing score is 70, most students did not pass the test E. The horizontal nature of the graph for the test scores of 60 and below indicates that those scores occurred most infrequently.
A
The graph below displays the relative frequency distribution for X, the total number of dogs and cats owned per household ... A) .170 B) .017 C) .790 D) .600 E) .260
A
The table below shows the results of a survey of 34 moviegoers given the statement, "There is too much violence in movies." Opinion Rating: Frequency Strongly Disagree: 2 Disagree: 7 No Opinion: 13 Agree: 5 Strongly Agree: 7 How much smaller is the proportion of respondents who strongly agreed with the statement than the proportion of all who disagreed? A. 0.059 B. 0.176 C. 0.206 D. 0.265 E. 0.382
A
A recent study was conducted to investigate the duration of time required to complete a certain manual dexterity task. The reported mean was 10.2 seconds with a standard deviation of 16 seconds. Suppose the reported values are the true mean and standard deviation for the population of subjects in the study. If a random sample of 144 subjects is selected from the population, what is the approximate probability that the mean of the sample will be more than 11 seconds? A. 0.1151 B. 0.2743 C. 0.7257 D. 0.8849 E. Based on the values of the true mean and standard deviation, it can be concluded that the population distribution is not normal and therefore the probability cannot be calculated.
B
A researcher interested in the age at which women are having their first child surveyed women having at least one child and found an approximately normal distribution with a mean age of 27.3 and a standard deviation of 5.4. Approx .95 of the women has their first child between the ages of A) 11.1 and 43.5 years B) 16.5 and 38.1 years C) 21.9 and 32.7 years D) 21.9 and 38.1 years E) 25.0 and 29.6 years
B
A researcher wishes to test a new drug developed to treat hypertension (high blood pressure). A group of 40 hypertensive men and 60 hypertensive women is to be used. The experimenter randomly assigns 20 of the men and 30 of the women to the placebo and assigns the rest to the treatment. The major reason for separate assignment for men and women is that A. It is a large study with 100 subjects B. The new drug may affect men and women differently C. The new drug may affect hypertensive and non-hypertensive people differently D. This design uses matched pairs to detect the new-drug effect E. There must be an equal number of subjects in both the placebo group and the treatment group
B
Five estimators for a parameter are being evaluated. The true value of the parameter is 0.Simulations of 100 random samples, each of sizen, are drawn from the population. For each simulatedsample, the five estimates are computed. The histograms below display the simulated samplingdistributions for the five estimators. Which simulated sampling distribution is associated with the best estimator for this parameter? too lazy
B
In one study on the effect of niacin on cholesterol level, 100 subjects who acknowledged being long-time niacin takers had their cholesterol levels compared with those of 100 people who had never taken niacin. In a second study, 50 subjects were randomly chosen to receive niacin and 50 were chosen to receive a placebo. a) The first study was a controlled experiment, while the second was an observational study. b) The first was an observational study, while the second was a controlled experiment. c) Both studies were controlled experiments. d) Both studies were observational studies. e) Each study was part controlled experiment and part observational study.
B
Joe and Matthew plan to visit a bookstore. Based on their previous visits to this bookstore, the probability distributions of the number of books they will buy are given below. Number of books Joe will buy 0: 0.5, 1: 0.25, 2: 0.25 Matthew will buy 0: 0.25, 1: 0.50, 2: 0.25 Assuming that Joe and Matthew make their decisions independently, what is the probability that they will purchase no books on this visit to the bookstore? A. 0.0625 B. 0.1250 C. 0.1875 D. 0.2500 E. 0.7500
B
Men's shirt sizes are determined by their neck sizes. Suppose that men's shirt sizes are approximately normally distributed with mean 15.7 inches and standard deviation 0.7 inch. A retailer sells men's shirts in sizes S, M, L, XL, where the shirt sizes are defined in the table below. Shirt Size: Neck Size S: 14 less than or equal to neck size less than 15 M: 15 less than or equal to neck size less than 16 L: 16 less than or equal to neck size less than 17 XL: 17 less than or equal to neck size less than 18 The retailer only stocks the sizes listed in the table above What proportion of customers request a size M shirt? A. The proportion of customers that request a size M shirt is approximately 0.57 B. The proportion of customers that request a size M shirt is approximately 0.5077 C. The proportion of customers that request a size M shirt is approximately 0.43 D. The proportion of customers that request a size M shirt is approximately 0.4923 E. The proportion of customers that request a size M shirt is approximately 0.1749
B
Suppose A and B are events in a sample space with P(A) = .80 and P(B|A)= .50. Then P( A and B) = ________? A. 0.3 B. 0.4 C. 0.625 D. 0.8 E. 1
B
The XYZ Office Supplies Company sells calculators in bulk at wholesale prices, as well as individually at retail prices. Next year's sales depend on the market conditions, but executives use probability to find estimates of sales for the coming year. The following tables are estimates for next year's sales. WHOLESALE SALES Number Sold: Probability 2,000: 0.10 5,000: 0.30 10,000: 0.40 20,000: 0.20 RETAIL SALES Number Sold: Probability 600: 0.40 1,000: 0.50 1,500: 0.10 What profit does XYZ Office Supplies Company expect to make next year if the profit from each calculator sold is $20 at wholesale and $30 at retail? A. $10,590 B. $220,700 C. $264,750 D. $833,100 E. $1,002,500
B
The admissions policy at a certain university requires that incoming students score in the upper 20% on a standardized test. If the mean score on the test is 510 and the standard deviation of the scores is 80, what its the minimum score that a student can earn on the test to meet the admissions requirement? Scores on the test are normally distributed and are reported in intervals of 10. A. 520 B. 580 C. 590 D. 600 E. 620
B
The box plots below summarize two data sets, A and B. Set A) Min- 10, Q1- 20, M- 30, Q3- 38, Max- 47 Set B) Min- 13, Q1- 22, M- 28, Q3- 38, Max- 44 Which of the following must be true? I. Set A contains more data than Set B. II. The box of Set A contains more data than the box of Set B. III. The data set in Set A has a larger range than the data in Set B. A. I only B. III only C. I and II only D. II and III only E. I, II, and III
B
The buyer for an electronics store wants to estimate the proportion of defective wireless game controllers in a shipment of 5,000 controllers from the store's primary supplier. The shipment consists of 200 boxes each containing 25 controllers. The buyer numbers the boxes from 001 to 200 and randomly selects six numbers in that range. She then opens the six boxes with the corresponding numbers, examines all 25 controllers in each of these boxes, and determines the proportion of the 150 controllers that are defective. What type of sample is this? A. Biased Random Sample B. Cluster Random Sample C. Simple Random Sample D. Stratified Random Sample E. Non Random Sample
B
The graph of two sampling distributions of a sample mean from the same random variable for samples of two different sizes are shown below. Which of the following statements must be true about the sample sizes? A) The sample size of I is less than the sample size of II. B) The sample size of I is greater than the sample size of II. C) The sample size of I is equal to the sample size of II. D) The sample size does not affect the sampling distribution. E) The sample sizes cannot be compared based on these graphs
B
The population {2,3,5,7} has mean mu= 4.25 and standard deviation 1.92. When sampling with replacement, there are 16 different possible ordered samples of size 2 that can be selected from this population. The mean of each of these 16 samples is computed. For example, 1 of the 16 samples is (2,5), which has a mean of 3.5. The distribution of the 16 sample means has its own mean and standard deviation. Which of the following statements is true? A) Ux = 4.25 and STDx = 1.92 B) Ux = 4.25 and STDx > 1.92 C) Ux = 4.25 and STDx < 1.92 D) Ux > 4.25 E) Ux < 4.25
B
The probability of obtaining a head when a certain coin is flipped is about 0.65. What is the probability that heads would be obtained 15 or fewer times when this coin is flipped 25 times? a. 0.14 b. 0.37 c. 0.39 d. 0.60 e. 0.65
B
In a carnival game, a person can win a prize by guessing which one of 5 identical boxes contains the prize. Which of the following describes the sampling distribution of x bar?
B (1 = 1/9, 1.5 = 2/9, 2 = 1/3, 2.5 = 2/5, 3 = 1/9)
A fair coin is flipped 10 times and the number of heads is counted. This procedure of 10 coin flips is repeated 100 times and the results are placed in a frequency table. Which of the frequency tables below is most likely to contain the results from these 100 trials? A. no B. no C. yes D. no E. no
C
A tetrahedral die has four sides numbered 1 through 4. Let X be a random variable that represents the sum of the numbers face up when two tetrahedral die are rolled. (graph of probabilities associated with sum) Sum: Probability 2: 1/16 3: 1/8 4: 3/16 5: 1/4 6: 3/16 7: 1/8 8: 1/16 What is the probability that the sum of the dice is more than 5? A. 0.001 B. 0.625 C. 0.375 D. 0.0004 E. Essentially 1
C
Aldrich Ames is a convicted traitor who leaked American secrets to a foreign power. Yet Ames took routine lie detector tests and each time passed them. How can this be done? Recognizing control questions, employing unusual breathing patterns, biting one's tongue at the right tie, pressing one's toes hard to the floor, and counting backwards by 7 are countermeasures that are difficult to detect but can change the results of a polygraph examination. In fact, it is reported in Professor Ford's book, that after only 20 minutes of instruction by "Buzz" Fay, a prison inmate, 85% of those trained were able to pass the polygraph examination even when guilty of a crime. Suppose that a random sample of nine students are told "a secret" and then given instructions on how to pass the polygraph examination without revealing their knowledge of the secret. What is the probability that more than half of the students are able to pass the polygraph examination? A. 0.0339 B. 0.0283 C. 0.9944 D. 0.9661 E. 0.9717
C
At a college the scores on the Chemistry final exam are approximately normally distributed, with a mean of 75 and a standard deviation of 12. The scores on the calculus final are also approximately normally distributed, with a mean of 80 and a standard deviation of 8. A student scored 81 on the chemistry final and 84 on the calculus final. Relative to the students in each respective class, in which subject did the student do better? A. The student did better in Chemistry B. The student did better in Calculus C. The student did equally well in each course D. There is no basis for comparison, since the subjects are different from each other and are in different departments E. There is not enough information
C
The back to back stem and leaf plot shown below can be used to compare the number of hours students at a local university spent studying. A random sample of chemical engineering students was selected and each student was asked the number of hours they spend studying per week. An independent random sample of mathematics majors was selected and students were asked the same question. Based on the distribution above, which of the following must be a false statement? A. The median number of hours spent studying per week is higher for chemical engineering than mathematics majors B. Chemical engineering major students tend to study for a longer period of time per week C. Both distributions appear to be roughly symmetric D. The mean number of hours spend studying per week is approximately the same for chemical engineering and mathematics majors E. The distribution of mathematics study hours has a smaller spread
C
The director of a fitness center wants to examine the effects of two exercise classes (spinning and aerobics) on body fat percentage. A six-week spinning class and a six-week aerobics class are offered at the same time and on the same days, so that a person can enroll in only one of them. A new class of each is about to begin, and each class has 25 people in it. Ten people are randomly selected from each class. Each person's body fat percentage is measured at the beginning and again at the end of the six-week class. Using the change in body fat percentage as the response variable and conducting a test, the director dete.rmines that there is a significant difference between the treatment means. Which of the following is a confounding variable in the study? (A) The director's choice of spinning and aerobics classes as the types for use in the study (B) The random sample of 10 people from each class. e) The participants' choice of which class to take (D) The use ofbody fat percentage as the measure of effectiveness ofthe treatment (E) The fact that both classes were conducted three times each week at the same time of day and for the same amount of time each day
C
The number of points, X, scored in a game has the probability distribution below. A) 0 B) 1 C) 2 D) 3 E) 4
C
The statistics below provide summary of the distribution of heights, in inches, for a simple random sample of 200 young children. Mean: 46 inches Median: 45 inches Standard Deviation: 3 inches First Quartile: 43 inches Third Quartile: 48 inches About 100 children in the sample have heights that are: A. Less than 43 inches B. Less than 48 inches C. Between 43 and 48 inches D. Between 40 and 52 inches E. More than 46 inches
C
Two friends Tom and Janice, have cars in desperate need of repair. On any given day, the probability that Tom's car will break down is 0.28, and the probability that Janice's car will break down is 0.67 since it is older than Tom's. If Tom and Janice's cars break down independently, of one another, what is the probability that Tom or Janice's car will break down? A. 0.950 B. 0.1876 C. 0.7624 D. 0.40 E. 0.2024
C
Under which of the following conditions is it preferable to use stratified random sampling rather than simple random sampling? A) The population can be divided into a large number of strata so that each stratum contains only a few individuals. B) The population can be divided into a small number of strata so that each stratum contains a large number of individuals C) The population can be divided into strata so that the individuals in each stratum are as much alike as possible D) The population can be divided into strata so that the individuals in each stratum are as different as possible. E) ) The population can be divided into strata of equal sizes so that each individual in the population still has the same chance of being selected
C
When the drug tamoxifen was first introduced to treat breast cancer, there was concern that it would cause osteoporosis as a side effect. To test this concern, cancer subjects were randomly selected and given tamoxifen, and their bone density was measured before and after treatment. Which of the following is a true statement? I. This study was an observational study II. This study was a sample survey of randomly selected cancer patients III. This study was an experiment in which the subjects were used as their own controls. A. I only B. II only C. III only D. I and II E. None of the above gives the complete set of true responses
C
When two fair dice are rolled simultaneously, what is the probability of getting a sum of 7 given that the first die rolled is an odd number? A) 1/12 B) 1/9 C) 1/6 D) 1/2 E) 1/4
C
. George and Michelle each claimed to have the better recipe for chocolate chip cookies. They decided to conduct a study to determine whose cookies were really better. They each baked a batch of cookies using their own recipe. George asked a random sample of his friends to taste his cookies and to complete a questionnaire on their quality. Michelle asked a random sample of her friends to complete the same questionnaire for her cookies. They then compared the results. Which of the following statements about this study is false? (a) Because George and Michelle have a different population of friends, their sampling procedure makes it difficult to compare the recipes. (b) Because George and Michelle each used only their own respective recipes, their cooking ability is confounded with the recipe quality. (c) Because George and Michelle each used only the ovens in their houses, the recipe quality is confounded with the characteristics of the oven. (d) Because George and Michelle used the same questionnaire, their results will generalize to the combined population of their friends. (e) Because George and Michelle each baked one batch, there is no replication of the cookie recipes
D
A high school statistics class wants to conduct a survey to determine what percentage of students in the school would be willing to pay a fee for participating in after-school activities. Twenty students are randomly selected from each of the freshmen, sophomore, junior, and senior classes to complete the survey. This plan is an example of which type of sampling? A. Cluster B. Convenience C. Simple Random D. Stratified Random E. Systematic
D
A random sample of 25 households from NBISD were surveyed. In this survey, data were collected on the age of the youngest child living in each household. The histogram below displays the data collected in the survey. Graph is frequency histogram. Intervals: 0-2, 4 freq 2-4, 1 freq 4-6, 2 freq 6-8, 5 freq 8-10, 3 freq 10-12, 8 freq 12-14, 2 freq In which of the following intervals is the median of these data located? A. O years old to less than 2 years old B. 4 years old to less than 6 years old C. 6 years old to less than 8 years old D. 8 years old to less than 10 years old E. 10 years old to less than 12 years old
D
An experiment has three mutually exclusive outcomes, A, B, and C. If P(A) = .12, P(B)= .61, and P(C) = .27, which of the following must be true? I. A and C are independent II. P(A^B)=0 III. P(B or C) = P(B) + P(C) A. I only B. I and II only C. I and III only D. II and III only E. I, II, and III
D
As a promotional gimmick, a cereal manufacturer packages boxes of cereal with CD-ROM's of popular games. A) (5 choose 3) B) (5 choose 3) C) (5 choose 1) D) (.8)^2(.2) E) (.2)^2(.8)
D
Home pregnancy tests have grown in popularity. Research shows that only 30% of those using a particular kit are actually pregnant. When a pregnant woman uses the kit, it correctly indicates pregnancy 96% of the time. A woman who is not pregnant gets a correct indication 90% of the time. What is the probability that a randomly selected woman gets a positive result? A. A randomly selected woman will get a positive result approximately 96% of the time B. A randomly selected woman will get a positive result approximately 86% of the time C. A randomly selected woman will get a positive result approximately 80% of the time D. A randomly selected woman will get a positive result approximately 36% of the time E. A randomly selected woman will get a positive result approximately 21% of the time
D
Ninety percent of the people who have a particular disease will have a positive result on a given diagnostic test. Ninety percent of the people who do not have the disease will have a negative result on this test. If 5 percent of a certain population has the disease, what percent of that population would test positive for the disease? A) 4.5% B) 5% C) 10% D) 14% E) 90%
D
Polly takes three standardized tests. She scores 600 on all three. Using standard scores, rank her performance on the three tests from best to worst if hte means and standard deviations are as follows. A) I, II, and III B) II,< II, and I C) I, III, and II D) III, I, and II E) II, I, and III
D
Suppose that public opinion in a large city is 35% against increasing taxes to support the public school system. If a random sample of 500 people from this city are interviewed, what is the approximate probability that more than 200 of these people will not be against increasing taxes? Which of the following set ups would answer the question? A. (500 choose 200)(O.65)^200(0.35)^300 B. (500 choose 200)(0.35)^200(0.65)^300 C. (500 choose 200)(0.65)^200(0.35)^300 + ... + (500 choose 500)(0.65)^500(0.35)^0 D. (500 choose 201)(0.65)^201(0.35)^299 + ...+ (500 choose 500)(0.65)^500(0.35)^0 E. (500 choose 0)(0.65)^0(0.35)^500 + ... + (500 choose 200)(0.65)^200(0.35)^300
D
The box plots shown above summarize two data sets, I and II. Based on the box plots, which of the following statements about these two data sets CANNOT be justified? A) The range of data set I is equal to the range of data set II B) The interquartile range of data set 1 is equal to the interquartile range of data set II C) The median of data set I is less than the median of data set II D) Data set I & data set II have the same number of data points E) About 75% of values in the data set are greater than or equal to about 50% of the values in data set 1
D
The heights of adult women are approximately normally distributed about a mean of 65 inches with a standard deviation of 2 inches. If Rachael is at the 99th percentile in height for adult women, then her height, in inches, is closest to A. 60 B. 62 C. 68 D. 70 E. 74
D
The number of sweatshirts, X, a tendon sells daily has the following probability distribution. If each sweatshirt sells for $25, what is the expected daily total dollar amount taken in by the vendon from the sale of sweatshirts? A) $5.00 B) $7.60 C) $35.50 D) $38.00 E) $75.00
D
To check the effect of cold temperature on the elasticity of two brands of rubber bands, one box of Brand A and one box of Brand B rubber bands are tested. Ten bands from the Brand A box are placed in a freezer for two hours and ten bands from the Brand B box are kept at room temperature. The amount of stretch before the breakage is measured on each rubber band, and the mean for the cold bands is compared to the mean for the others. Is this a good experimental design? A. No, because the means are not proper statistics for comparison. B. No, because more than two brands should be used. C. No, because more temperatures should be used. D. No, because temperature is confounded with brand. E. Yes this is a good experimental design.
D
The histogram below displays the time in minutes needed for each chimpanzee in a sample of 26 to complete a simple navigational task Too lazy bnlerhgw97ehw9he
D) Left end point at 0, median at 20, Q3 at 40
A new medication has been developed to treat sleep-onset insomnia (difficulty in falling asleep). Researchers want to compare this drug to a drug that has been used in the past by comparing the length of time it takes subjects to fall asleep. Of the following, which is the best method for obtaining this information? A. Have subjects choose which drug they are willing to use, then compare the results. B. Assign the two drugs to the subjects on the basis of their past sleep history without randomization then compare the results. C. Give the new drug to all subjects on the first night. Give the old drug to all subjects on the second night. Compare the results. D. Randomly assign the subjects to two groups, giving the new drug to one group and no drug to the other group, then compare the results. E. Randomly assign the subjects to two groups, giving the new drug to one group and the old drug to the other group, and compare the results.
E
At a certain high school, all students who take AP Psychology also take AP Statistics. From past records, the probability that a student gets a 5 in AP Psychology is one- fourth. The probability a student gets a 5 on the AP Statistics exam is one-seventh. What is the probability that a student will get at least one five when taking both exams? I. If the events are independent? II. If the students getting a 5 on the AP stats exam are a subset of those students getting a 5 on the AP Psych exams? A) 11/28, 1/4 B) 11/28, 1/7 C) 9/28, 1/7 D) 9/28, 1/4 E) 5/14, 1/4
E
For a set of values, suppose the mean is 10 and the standard deviation is 2. If each value is multiplied by 9, what will be the mean and the standard deviations or this new set of values? A) Mean 10; std 2 B) Mean 10; std 18 C) Mean 90; std 2 D) Mean 90; std 6 E) mean 90; std 18
E
Jana collected data on the amount of time in minutes each person in a large sample of customers spent in a classic car museum. While gathering her data, Jana decided to categorize each customer by his or her gender as well. She then generated the parallel box plots shown below. Based on the box plots, which of the following statements is true? Female: Min- 5 Q1- 7 Median- 15 Q3- 16 Max- 20 Male: Min- 5 Q1- 10 Median- 20 Q3- 29 Max- 45 Outliers at 60 and 90 A. The range of the amount of time (in minutes) males in the sample of customers spent in the museum is approx. 40 minutes B. The mean amount of time (in minutes) males in the sample spent in the museum is approx. 20 minutes C. The third quartile of the amount of time (in minutes) males in the sample spent in the museum is 45 minutes D. The IQR of the amount of time (in minutes) females in the sample spent in the museum is 15 minutes E. Approximately half of the males in the sample of customers spent at least as much time in the museum as any female in the sample of customers
E
John wants to determine how age and gender are related to political party preference in his town. Voter registration lists are stratified by gender and age group. John selects a simple random sample of 50 men from the 20 to 29 age group and records their age, gender, and party registration. He also selects an independent simple random sample of 60 women from the 40 to 49 age group and records the same information. Of the following, which is the most important observation about John's plan? A) The plan is well conceived and should serve the intended purpose. B) His samples are too small. C) He should have used equal sample sizes. D) He should have randomly selected the two age groups instead of choosing them non-randomly. E) He will be unable to tell whether a different in party affiliation is related to differences in age or to the difference in gender
E
Suppose the probability of encountering an American who practices a particular religion is 0.014. What are the mean and standard deviation for the number of Americans in a random sample of 500 who practice this religion? A. mean 0.014; standard deviation 0.0006 B. mean 0.014; standard deviation 0.0053 C. mean 7; standard deviation 0.0006 D. mean 7; standard deviation 0.0053 E. mean 7; standard deviation 2.627
E
The Physicians' Health Study, a large medical experiment involving 22,000 male physicians, attempted to determine whether aspirin could help prevent heart attacks. In this study, one group of about 11,000 physicians took an aspirin every other day, while a control group took a placebo. After several years, it was determined that the physicians in the group that took aspirin had significantly fewer heart attacks than the physicians int he control group. Which of the following statements explains why it would not be appropriate to say that everyone should take an aspirin? I) The study included only physicians, and different results may occur in individuals in other occupations. II) The study included only males and there may be different results with females. III) Although taking aspirin may be helpful in preventing heart attacks, it may be harmful to some other aspects of health. A) I B) II C) III D) II and III E) I, II, III
E
The table below shows the sample size, the mean, and the median for two samples of measurements. What is the median for the combined sample of 47 measurements? too difficult to write out lbeheheh
It cannot be determined from the information given.