Stats Quiz's
If a binomial distribution has p = .30, then q = ____. .30 .50 .701 .30
.70
For a binomial distribution with p = 1/4 and n = 36, what is the range of possible values for X? 0 to 1 0 to 36 1 to 36 0 to 1/4
0 to 36
It is known that the lengths of songs played on a radio station follow a normal distribution with mean 3.9 minutes and standard deviation 0.4 minutes. A sample of 16 songs is randomly selected. What is the standard deviation of the sampling distribution of the sample mean length? 0.025 minutes 0.1 minutes 3.9 minutes 16 minutes
0.1 minutes
A tennis team has 14 players on its roster. A tennis player is selected at random to play in a conference tournament. In this scenario, what is the total number of outcomes?
14
In a frequency distribution graph, the frequency values are presented on the horizontal axis and the scores (or measurement categories) are presented on the vertical axis. True or False
False
The binomial distribution for p = 1/4 and n = 48 has a mean of 𝜇 = 24. True or False
False
Given a probability density curve of a continuous random variable, what needs to be done to determine the probability of a particular interval of values that a continuous random variable can have? Use table of random numbers. Calculate the mean. Add the probabilities of values of the variable in the interval. Find the area of the region bounded by the endpoints of the interval.
Find the area of the region bounded by the endpoints of the interval.
There are three factors that affect the probability of a Type II error: level of significance, sample size, and true value of the population parameter. Is the following statement true or false? A larger level of significance will reduce the probability of a Type II error. True or False
True
A reading specialist takes a sample of 25 students and determines that their average reading level is different than the population mean of that age group. The reading specialist will reject the null hypothesis based on this sample. In this situation, if this conclusion is wrong, then the specialist just made a ________.
Type I error
We have two conclusions we can make as a result of a hypothesis test: reject the null hypothesis and conclude the alternative OR fail to reject the null hypothesis and then we cannot conclude the alternative hypothesis. Sometimes we make mistakes, so if we reject the null hypothesis but it was true, then we just made a _______ .
Type I error
Will this summer be especially hot? The Farmer's Almanac is calling for a particularly hot summer this year. A student would like to estimate the average temperature using a thermometer that she places outside. Prior to the start of summer, the student randomly selects 10 days that she will use as her sample. On each of those 10 days, she records the outside temperature at 3 p.m. Assume that all conditions for inference have been met. (a) After collecting her data, the student calculates a 95% confidence interval to estimate the population mean. In this case, what is the population? (b) Suppose the calculated confidence interval is (72, 90) degrees Fahrenheit. What is the value of the point estimate (in degrees Fahrenheit)? (c) Based upon your calculated point estimate and the confidence interval given in Part (b), what is the estimated margin of error (in degrees Fahrenheit)?
all days for that summer 81 9
(a) Fill in the blank. The smaller the desired margin of error (M) is, the ______ the sample size must be. (b) Determine whether the following statement is true or false. The sample size must always be a natural number.
larger true
It is known that the lengths of songs played on a radio station follow a normal distribution with mean 3.7 minutes and standard deviation 0.4 minutes. A sample of 4 songs is randomly selected. What is the shape of the sampling distribution of the sample mean length? normal uniform left skewed right skewed
normal
A frequency distribution is a tabular summary of data showing the _____ of items in several classes. relative percentage percentage number fraction
number
What does the symbol 𝜎 represent? population standard deviation sample standard deviation population mean sample mean
population standard deviation
A reading specialist takes a sample of 20 students and determines that their average reading level is different from the population mean of that age group. In this situation, the hypothesis test will be which of the following? lower-tail test upper-tail test two-tail test cannot be determined
two-tail test
With the current equipment owned, a manufacturing plant is supposed to be able to produce 110 bottles of syrup every hour. When the machine malfunctions, it sometimes goes too fast, and then deformities occur. Other times, it malfunctions by moving too slowly, also causing deformities to the product. The machine's peak performance is maintained by keeping production as close to 110 bottles per hour as possible. (c) Define the appropriate hypothesis test. lower-tail test upper-tail test two-tail test cannot be determined
two-tail test
Sixty randomly selected married couples with children from the state of Louisiana were surveyed and asked to identify if they are in agreement with the disciplinary actions their spouse uses to address issues with their children. From those surveyed, 63% were in agreement with their spouse on methods of disciplining their children. Fill in the blanks. The 60 randomly selected married couples surveyed from the state of Louisiana are the _______ , and 63% is a _____. Determine whether the following statement is true or false. The population of interest in this study is all married couples with children.
Sample Statistic false
Events A and B are mutually exclusive. If P(A) = 0.28 and P(B) = 0.39, find the following. (a). P(A ∪ B) (b). P(A ∩ B)
0.67 0
A fashion designer has created an elegant gown but is unsure how many stripes to put on the gown. The designer makes dresses with one, two, three, and no stripes. A marketing firm then selects a random sample of 1,000 people, who say they are interested in fashion, to give their opinion on which dress they find most appealing. Let x = the number of stripes in the dress. The probability distribution for x is as follows. x. 0. 1. 2 3 p(x). 0.48. 0.14. 0.15. 0.23 (a). What is the probability that a person liked no stripes on the dress? (b) Determine whether the following statement is true or false. The probability that a person liked two or three stripes on the dress is 0.28.
(0.48) False
A student conducts a simple random sample of students from her high school and finds that 21 out of 100 students in her sample regularly walk to school. Give a point estimate for the proportion of all students at her high school who regularly walk to school.
0.21
It is estimated that 80% of people with type 2 diabetes are overweight. Assume a sample size of 105. (a) What is the value of the point estimate? 80 0.80 2 105 (b) How many people in the sample are overweight?
0.80 84
A sample of n = 5 scores has M = 20 and s2 = 4. What is the sample standard deviation? 16 sqrt 20 2 5
2
The concentration of salt in seawater (salinity) is approximated to be 35 parts per thousand. There are 2 saltwater ponds in the county. A student visits each pond and takes 30 samples of water from multiple spots in each pond and measures the salinity of the water. (a) If the hypotheses are H0: 𝜇1 − 𝜇2 = 0 and Ha: 𝜇1 − 𝜇2 ≠ 0, is this test a 1-tailed or a 2-tailed test? (b) Can you assume normality? (c) Are the 2 samples independent? (d) If the calculated P-value is 0.0374 and 𝛼 = 0.05, what decision should be made about the null hypothesis? Because 0.0374 > 𝛼, we reject the null hypothesis. Because the 0.0374 < 𝛼, we reject the null hypothesis. Because the 0.0374 > 𝛼, we fail to reject he null hypothesis. Because the 0.0374 < 𝛼, we fail to reject the null hypothesis.
2 tailed test yes yes Because the 0.0374 < 𝛼, we reject the null hypothesis.
A nutritionist asks a client to record the number of calories he consumes each day for 6 months. The distribution of calories can be modeled with a normal distribution. What is the likelihood that the client consumed an amount of calories that was more than 2 standard deviations above the mean on any randomly chosen day? (Use the Empirical Rule.) 2.5% 5% 16% 32%
2.5%
On a given day, the ages of people arrested in New York City can be modeled with a normal distribution. (a) What percent of arrested individuals have ages that are more than 2 standard deviations above the mean? (Use the Empirical Rule.) (b) If the mean age of an arrested person is 30 with a standard deviation of 5, find the z-score of an arrested person who is 32 years old.
2.5% 0.4
It is known that the lengths of songs played on a radio station follow a normal distribution with mean 3.7 minutes and standard deviation 0.4 minutes. A sample of 25 songs is randomly selected. What is the mean of the sampling distribution of the sample mean length? 0.016 minutes 0.08 minutes 3.7 minutes 25 minutes
3.7 minutes
Suppose that you calculated the sample size needed to estimate a population mean within a given margin of error when 𝜎 is known, and the answer came out to n = 31.02. How many items should be sampled? 31.02 32 30 31
32
With the current equipment owned, a manufacturing plant is supposed to be able to produce 15 bottles of syrup every hour. When the machine malfunctions, it sometimes begins going too fast, and then deformities occur. Other times, it malfunctions by moving too slowly, also causing deformities to the product. The machine's peak performance is maintained by keeping production as close to 15 bottles per hour as possible. A quality control supervisor takes a random sample of hours and counts the number of bottles produced in order to test whether the machine is functioning correctly or whether it needs to be readjusted. (b) Which of the following sample sizes could be taken to ensure that the sampling distribution of x is approximately normal? 4 20 21 41
41
What is the median for the following set of scores? Scores: 1, 2, 5, 6, 17 3.5 5 5.5 6
5
Determine whether the following statement is true or false. Two events are independent if P(A ∩ B) = P(A) + P(B). true or false
False
A large taxi company in a major U.S. city keeps track of the distance traveled on each fare. Suppose that the distribution of distance per fare is normally distributed with mean 9 miles and standard deviation 2.0 miles. (a) Find the mean (in miles) of the sampling distribution of the mean distance per fare for a sample of 16 fares. (b) Find the standard deviation (in miles) of the sampling distribution from part (a). Fill in the blanks. If the sample size increases to 25 fares, the probability that the mean distance is between 8 and 10 miles will _________ , because the standard deviation of the sampling distribution of the mean distance will ________.
9 0.5 increase decrease
Which of the following samples would have the largest value for sample variance? 1, 3, 5 11, 13, 15 51, 53, 55 All the samples would have exactly the same variance.
All the samples would have exactly the same variance.
According to a study published in the American Journal of Preventive Medicine, weight gain of college freshman may be related to a decrease in activity level after starting college. What is one way to test this hypothesis using a mean difference for a paired sample? Compare the mean differences in weight at the beginning and end of a school year in a sample of freshmen. Compare the mean of the differences in weight at the beginning and end of a school year for a random sample of freshmen. Compare the mean differences in weight at the beginning and end of a school year in freshman females who regularly eat on campus versus those who eat in their dorms or off campus. Compare the mean of the differences in weight at the beginning and end of a school year in freshman female athletes to freshman male athletes.
Compare the mean of the differences in weight at the beginning and end of a school year for a random sample of freshmen.
Determine whether the following statement is true or false. A Poisson distribution counts the number of successes among a fixed number of trials. True or False
False
Determine whether the following statement is true or false. A z-score tells you how many standard deviations a data value is from the median. True or False
False
A political analyst wants to see if ratings for a particular candidate improve after a debate with the candidate's opponent. The analyst polls a group of 20 respondents who previously indicated they had not yet decided on a candidate on a rating scale, with 1 being "I would most certainly NOT vote for this candidate" and 10 being "I would most certainly vote for this candidate." The mean difference for this paired sample is defined as the difference between post- and pre-ratings or 𝜇d = 𝜇post − 𝜇pre. Determine whether the following statement is true or false. The null hypothesis is H0: 𝜇d = 0. The alternative hypothesis is Ha: 𝜇d ≠ 0. True or False
False
A botanist believes that pumpkin patches must be treated with a fungicide on average 5 times over the course of their growing season in order to maintain optimal plant health. However, he is curious about whether the pumpkins could do equally as well with fewer treatments. State the appropriate null and alternative hypotheses.
H = 5 H < 5
With the current equipment owned, a manufacturing plant is supposed to be able to produce 110 bottles of syrup every hour. When the machine malfunctions, it sometimes goes too fast, and then deformities occur. Other times, it malfunctions by moving too slowly, also causing deformities to the product. The machine's peak performance is maintained by keeping production as close to 110 bottles per hour as possible. (a) State the null hypothesis. H0: 𝜇 > 110 H0: 𝜇 = 110 H0: 𝜇 < 110 H0: 𝜇 ≠ 110
H0: 𝜇 = 110
The average age a child learns to read is 6 years. Do boys and girls learn to read at the same mean age, or do boys learn to read earlier than girls on average? What is the appropriate null hypothesis? H0: 𝜇boys − 𝜇girls ≠ 0 H0: 𝜇boys − 𝜇girls > 0 H0: 𝜇boys − 𝜇girls < 0 H0: 𝜇boys − 𝜇girls = 0
H0: 𝜇boys − 𝜇girls = 0
With the current equipment owned, a manufacturing plant is supposed to be able to produce 110 bottles of syrup every hour. When the machine malfunctions, it sometimes goes too fast, and then deformities occur. Other times, it malfunctions by moving too slowly, also causing deformities to the product. The machine's peak performance is maintained by keeping production as close to 110 bottles per hour as possible. (b) State the alternative hypothesis if we are testing whether the machine is causing deformities. Ha: 𝜇 > 110 Ha: 𝜇 = 110 Ha: 𝜇 < 110 Ha: 𝜇 ≠ 110
Ha: 𝜇 ≠ 110
If E and F are mutually exclusive events, then which of the following must be true? P(E) + P(F) = 1 P(E) − P(F) = 0 P(E ∩ F) = 0 P(E ∪ F) = 1
P(E ∩ F) = 0
If E and F are mutually exclusive events, then which of the following must be true? P(E) − P(F) = 0 P(E ∪ F) = 1 P(E ∪ F) = P(E) + P(F) P(E) + P(F) = 1
P(E ∪ F) = P(E) + P(F)
A test of significance produces a P-value of 0.025. Which of the following conclusions is appropriate? Fail to reject the null hypothesis at the 𝛼 = 0.05 level. Reject the null hypothesis at the 𝛼 = 0.05 level. Reject the alternative hypothesis at the 𝛼 = 0.05 level. Accept the null hypothesis at the 𝛼 = 0.05 level.
Reject the null hypothesis at the 𝛼 = 0.05 level.
The standard deviation describes the spread of the data points around the mean. T or F
T
A botanist for a large rose farm is told that the company currently averages 8 thousand roses per year. The company hires her to work as an outside consultant in order to increase their annual rose production. The hypotheses are given. H0: 𝜇 = 8 thousand Ha: 𝜇 > 8 thousand (a) Define what a Type I error is in the context of this problem. The company concludes that it produces 8 thousand roses per year on average, when it is actually producing more. The company concludes that it produces less than 8 thousand roses per year, when it really is producing 8 thousand roses. The company concludes that it produces more than 8 thousand roses per year, when it really is producing 8 thousand roses. The company concludes that it produces 8 thousand roses per year, when it really is producing less.
The company concludes that it produces more than 8 thousand roses per year, when it really is producing 8 thousand roses.
A botanist for a large rose farm is told that the company currently averages 8 thousand roses per year. The company hires her to work as an outside consultant in order to increase their annual rose production. The hypotheses are given. H0: 𝜇 = 8 thousand Ha: 𝜇 > 8 thousand (b) State the consequences of making a Type I error in the context of this problem. The company rewards the consultant for increasing annual production, when really production has stayed the same. The company rewards the consultant for increasing annual production, when really production has decreased. The company fires the consultant because it thinks annual production has decreased in spite of the consultant's work, when really it has stayed the same. The company fires the consultant because it thinks annual production has stayed the same in spite of the consultant's work, when really it has increased.
The company rewards the consultant for increasing annual production, when really production has stayed the same.
If the sample size is held constant and the confidence level increases, what happens to the margin of error? The margin of error stays the same. The margin of error could increase or decrease The margin of error decreases. The margin of error increases.
The margin of error stays the same.
A pharmaceutical company wants to estimate the mean response time for a supplement to reduce blood glucose levels in diabetic patients. Two hundred twenty-five patients with diabetes are randomly selected to participate in the study. (a) What is the population of interest in this study? (b) Determine whether the following statement is true or false. The sample obtained in this study is the 225 randomly selected patients with diabetes.
The population of interest in this study is all patients with diabetes . true
According to a particular survey of 1,600 dog owners, approximately 64% of all American dog owners are owners of only one dog. Identify the population of interest and sample in this scenario. The population of interest is _________ and sample is ____________ .
The population of interest is all American dog owners and sample is 1,600 dog owners .
The range, the interquartile range, and the standard deviation, are all measures of spread or variation. True or False
True
A fashion designer noticed that 20% of clothing from a particular factory had a defect. The designer is interested in how many pieces of clothing she will have to go through to find the first defect on a piece of clothing. What condition for a binomial probability distribution does this scenario violate? The probability of success is the same for each trial. Each trial can result in one of only two possible outcomes, labeled success (S) and failure (F). There is a fixed number of trials. Outcomes of different trials are independent.
There is a fixed number of trials.
A concert venue is located 3 minutes from a large university. A group of students are planning to attend the concert and think they can get there in less time. They test this hypothesis by using social media to survey a sample of other drivers to see how long this trip took them. The null and alternative hypotheses are given. H0: 𝜇 = 3 Ha: 𝜇 < 3 (b) What are the consequences of making a Type II error in the context of this problem? They conclude it will average fewer than 3 minutes, but the real average is 3 minutes to get there. They conclude it will average 3 minutes to get there, but the real average is less than 3 minutes. They conclude that it will average more than 3 minutes, but the real average is 3 minutes to get there. They conclude it will average fewer than 3 minutes to get there, but the real average is more than 3 minutes.
They conclude it will average 3 minutes to get there, but the real average is less than 3 minutes.
A concert venue is located 3 minutes from a large university. A group of students are planning to attend the concert and think they can get there in less time. They test this hypothesis by using social media to survey a sample of other drivers to see how long this trip took them. The null and alternative hypotheses are given. H0: 𝜇 = 3 Ha: 𝜇 < 3 (a) What is the consequence of a Type I error in the context of this problem? They conclude it will average fewer than 3 minutes, but the real average is 3 minutes to get there. They conclude it will average 3 minutes to get there, but the real average is less than 3 minutes. They conclude that it will average more than 3 minutes, but the real average is 3 minutes to get there. They conclude it will average fewer than 3 minutes to get there, but the real average is more than 3 minutes.
They conclude it will average fewer than 3 minutes, but the real average is 3 minutes to get there.
A distribution can have more than one mode. True or False
True
A distribution of scores has a mean of 84 and a median of 80. Based on this information it appears that the distribution is positively skewed. True or False
True
A researcher records how much time each participant needs to solve a series of problems. This is an example of a continuous variable. True or False
True
A researcher records the gender of each child born in the county hospital during the month of June. This researcher is measuring a discrete variable. True or False
True
Determine whether the following statement is true or false. The sum of all the probabilities of the discrete random variable's values must equal 1.
True
Determine whether the following statement is true or false. (Use the Empirical Rule.) If data are from a normal distribution, the percent of values that are more than 2 standard deviations from the mean is 5%. True or False
True
For a population, variance is the average squared distance from the mean. True or False
True
In the formula for sample variance, SS is divided by n − 1 to obtain a more accurate estimate of the population variance.
True
How often do you pray? A researcher is interested in determining if there is a relationship between frequent prayer and good health. He begins by asking a random sample of 25 people to estimate how many times they pray in a period of 1 week. Suppose a 95% confidence interval for the population mean is found to be (14, 44). Which of the following options is correct? We can be 95% confident that between 14 and 44 people pray each week. We can be 95% confident that the true mean number of times people pray each week is between 14 and 44 times. Between 14% and 44% of people pray. Ninety-five percent of people pray between 14 and 44 times each week.
We can be 95% confident that the true mean number of times people pray each week is between 14 and 44 times.
When should a t distribution be used? We do not know the value of the population standard deviation. 𝜎 is known. We use a confidence level of 95%. We are estimating a population proportion.
We do not know the value of the population standard deviation.
Public opinion polls on the president of the United States are testing to see if likeability has increased over the past year. The average likeability a year ago was 52%. The current polls show an average likeability of 56%. H0: 𝜇 = 0.52 Ha: 𝜇 > 0.52 After conducting the test, the P-value is 0.09. Based on 𝛼 = 0.05, what is the correct conclusion for the hypothesis test?
We would fail to reject the null hypothesis. This means that on the basis of the evidence, you cannot conclude that the mean amount of likeability for the president of the United States is greater than 0.52.
A chemist believes that corn fields must be treated with a fertilizer on average 7 times over the course of the growing season in order to maintain optimal plant growth. However, she is curious about whether the corn could do equally as well with fewer treatments. The null hypothesis would be H0: 𝜇 = 7. The alternative hypothesis would be Ha: 𝜇 < 7. What would a Type I error be in this situation? We would say that fewer treatments work when we really need 7. We would say that 7 treatments work when we really need fewer. We would say that more treatments are needed when we need fewer. We would say 7 treatments work when we really need more.
We would say that fewer treatments work when we really need 7.
Thompson Musical Instruments is moving to a new store. They have two locations in mind: Uptown Place and Downtown Mall. They have determined that 60% of their current customers shop at Uptown Place and that 70% shop at Downtown Mall. The probability that a current customer shops at both places is 42%. Are the events for their current customers, U = Shopping at Uptown Place and D = Shopping at Downtown Mall, independent? Yes No
Yes
While driving cross-country on a family vacation, the children ask, "Are we there yet?" an average of 15 times every hour. We will assume independence holds, that one child asking does not change the likelihood another will ask (or not ask). (a) Is the number of times the children ask, "Are we there yet?" in a 5-minute time period a Poisson random variable? Yes or No (b) What is the mean number of times the children ask this question in a 5-minute time period? (c) What is the standard deviation of the number of times the children ask this question in a 5-minute time period? (Round your answer to two decimal places.)
Yes
What is the most common graphical presentation of quantitative data? a dot plot a bar chart a pie chart a histogram
a histogram
Fifteen percent of the students in a school of Business Administration are majoring in Economics, 20% in Finance, 35% in Management, and 30% in Accounting. Which graphical device(s) can be used to present these data? a line chart only a bar chart both a bar chart and a pie chart only a pie chart
both a bar chart and a pie chart
For any set of data, the sum of the deviation scores will always be _____. equal to zero greater than zero less than zero impossible to determine without more information
equal to zero
The difference between the point estimate and the true population parameter is known as which of the following. point estimate error critical value sample
error
An employee satisfaction survey yields a mean result, 𝜇 = 3.7, and a standard deviation, 𝜎 = 0.5. The survey responses were normally distributed. Determine whether the following statement is true or false. The mean 𝜇 would correspond to the 40th percentile. true or false
false
According to Investopedia.com, the average person in their 30s has about $45,000 saved for retirement. Are men or women in their 30s more prepared for retirement? You sample 80 women in their 30s and find that their average retirement savings is $46,900. You also sample 80 men in their 30s and find that their average retirement savings to be $43,700. You want to know whether women save more than men on average. (a) Determine whether the following statement is true or false. It is important that the sample sizes are equal. True or False (b) $46,900 is which of the following? parameter or statistic (c) What sign is most appropriate for the alternative hypothesis? Ha: 𝜇w − 𝜇m _ 0
false statistic >
A researcher is interested in the amount of time it takes lab rats to complete a maze and find the food at the end. He measures the completion times for 20 rats and wants to display them with a graphical representation. The best type of display would be which of the following? Histogram Bar chart pie chart scatterplot
histogram
A large pharmaceutical company announces that the mean time for a new medicine to start working is less than 13 minutes. The alternative hypothesis is Ha: 𝜇 < 13. What type of hypothesis test is being described in the statement? lower-tail test upper-tail test two-tail test cannot be determined
lower-tail test
Complete the following sentence. The _____ of a discrete random variable is also known as the expected value.
mean
Who studies more, college freshmen or college seniors? Some argue that as freshmen, students are more worried about their education and spend much more time in the library preparing than upperclassmen. Others argue that by the senior year, classes are much more advanced and challenging and require many more hours of preparation than the introductory classes they took as freshmen. Given the following hypotheses, what is the appropriate definition of 𝜇f? H0: 𝜇f − 𝜇s = 0Ha: 𝜇f − 𝜇s≠0 mean number of hours spent studying for all freshmen mean number of hours spent studying for all freshmen in the sample mean number of hours spent studying for all college students mean number of hours spent studying for all students in the sample
mean number of hours spent studying for all freshmen
The sampling distribution of the sample mean is approximately normal when which of the following are true? (Select all that apply.) n ≥ 30 n ≥ 10 n ≤ 30 The population distribution is approximately normal.
n ≥ 30 The population distribution is approximately normal.
A teacher would like to know the average number of hours each night students spend completing homework. Which term best describes the true mean number of hours each night students spend completing homework? statistic population sample parameter
parameter
Which of the following symbols identifies the sample standard deviation? s s2 𝜎 𝜎2
s
A box of granola cereal from a particular brand labeled "NET WT. 15 OZ" should have 15 ounces or more of cereal inside. Forty-seven of these boxes were randomly selected and their contents were weighed. What is the 47 boxes of granola cereal in this study? Determine whether the following statement is true or false. The population of interest in this study is all cereals of this particular brand.
sample false
(a) What does p̂ stand for? sample mean sample proportion population proportion population mean (b) Given a confidence interval (0.08, 0.22), what is the margin of error?
sample proportion 0.07
The variability of the scores in a sample tends to be _________ the variability of the scores in the population from which the sample was obtained.
smaller than the
Complete the statement. The _____ normal distribution is a special case of the normal distribution. It is the distribution that occurs when a normal random variable has a mean of 0 and a standard deviation of 1 (𝜇 = 0 and 𝜎 = 1).
standard
An athletic trainer takes a sample of 25 athletes and determines that their average body mass index is 19. In this situation, the value 19 is which of the following? sample parameter population statistic
statistic
Do people who work in manufacturing earn more than workers in other industries? From 2 independent samples, salaries in manufacturing averaged $32.83 per hour compared to salary averages across other industries at $30.64 per hour. Is $32.83 a statistic or a parameter? statistic or parameter
statistic
(a) A numeric characteristic of a sample is called which of the following? (b) A numeric characteristic of a population is called which of the following? parameter sample population statistic (c) If all conditions are met, which of the following distributions is appropriate for calculating a confidence interval for a population mean when 𝜎 is known? uniform discrete binomial normal
statistic parameter normal
A psychologist found a study which claiming that 32% of patients who visit a psychologist have symptoms of anxiety. This psychologist had 37 patients visit. Let x = the number of patients that had symptoms of anxiety. (a) The random variable is which of the following? the number of psychologists the number of patients who had symptoms of anxiety the number of patients without symptoms of anxiety the number of patients who visited the psychologist How many total patients did the psychologist have visit? Determine whether the following statement is true or false. This scenario is an example of a binomial probability distribution. True or False
the number of patients who had symptoms of anxiety 37 True
A cumulative relative frequency distribution shows the proportion of data items with values less than or equal to the lower limit of each class. the percentage of data items with values less than or equal to the upper limit of each class. the proportion of data items with values less than or equal to the upper limit of each class. the percentage of data items with values less than or equal to the lower limit of each class.
the proportion of data items with values less than or equal to the upper limit of each class.
Determine whether the following statement is true or false. A negative z-score means that a data value is below the mean. true or false
true
In all states, first-offense DUI is classified as a misdemeanor and punishable by up to 6 months in jail. A lawyer believes that the average sentence served by males prosecuted of DUI is longer than the average sentence served by females prosecuted for the same crime. She asks her administrative assistant to pull samples from the state records of 120 male convicts and 120 female convicts who were charged with DUI and record the average length of sentence served for each sample. (a) Are the 2 samples independent? Yes or No (b) What is/are the parameter(s) in this problem? (c) What is/are the statistic(s) in this problem?
yes There are 2—the mean sentence served by all male criminals convicted of DUI in this state and the mean sentence served by all female criminals convicted of DUI in this state. There are 2—the mean sentence served by the 120 sampled male criminals convicted of DUI in this state and the mean sentence served by the 120 sampled female criminals convicted of DUI in this state.
Which of the following symbols represents the "union" of events? ∪ P(A and B) Ac ∩
∪
With the current equipment owned, a manufacturing plant is supposed to be able to produce 15 bottles of syrup every hour. The machine's peak performance is maintained by keeping production as close to 15 bottles per hour as possible. A quality control supervisor takes a random sample of hours and counts the number of bottles produced in order to test whether the machine is functioning correctly or whether it needs to be readjusted. (c) Define the population parameter of interest. 𝜇 = the number of bottles with deformities produced each day 𝜇 = the number of bottles with deformities produced each hour 𝜇 = the mean number of bottles produced by this machine each day 𝜇 = the mean number of bottles produced by this machine each hour
𝜇 = the mean number of bottles produced by this machine each hour
The mean of the sampling distribution of x is denoted by which of the following? 𝜇 denotes x-bar 𝜇 x bar 𝜎 denotes x-bar
𝜇 denotes x-bar
What is the missing piece of information that tells us to use a t test and not a z test? Select what is NOT known in a t test. 𝜇 x bar 𝜎 n
𝜎
Which of the following symbols identifies the population variance? 𝜎 𝜎2 s2 s
𝜎2
Which is the correct formula for the standard deviation of the sampling distribution of a sample mean? 𝜎x = n/sqrt 𝜎 𝜎 = 𝜎x/sqrt n 𝜎x = sqrt n/𝜎 𝜎x = 𝜎/sqrt n
𝜎x = 𝜎/sqrt n