Deck 9: Hypothesis Testing

Question 1

Which of the following types of tests may be performed?

A)Right-tailed and two-tailed tests
B)Left-tailed and two-tailed tests
C)Right-tailed and left-tailed tests
D)Right-tailed,left-tailed,and two-tailed tests

Answer 1

Right-tailed,left-tailed,and two-tailed tests

Question 2

The null hypothesis in a hypothesis test refers to _____________.

A)The desired outcome
B)The default state of nature
C)The altered state of nature
D)The desired state of nature

Answer 2

The default state of nature

Question 3

Under the assumption that the null hypothesis is true as an equality,the p-value is the likelihood of observing a sample mean that is at least as extreme as the one derived from the given sample.

Answer 3

True

Question 4

A Type I error is committed when we reject the null hypothesis which is actually true.

Question 5

The critical value approach specifies a range of values,also called the rejection region,such that if the value of the test statistic falls into this range,we do not reject the null hypothesis.

Question 6

For a given sample size,any attempt to reduce the likelihood of making one type of error (Type I or Type II)will increase the likelihood of the other error.

Question 7

A local courier service advertises that its average delivery time is less than 6 hours for local deliveries.When testing the two hypotheses, and ,μ stands for _____________.

A)The mean delivery time
B)The standard deviation of the delivery time
C)The number of deliveries that took less than 6 hours
D)The proportion of deliveries that took less than 6 hours

Question 8

A Type II error is made when we reject the null hypothesis and the null hypothesis is actually false.

Question 9

It is generally believed that no more than 0.50 of all babies in a town in Texas are born out of wedlock.A politician claims that the proportion of babies that are born out of wedlock is increasing.Identify the correct null and alternative hypotheses to test the politician's claim.

A)
B)
C)
D)

Question 10

In a one-tailed test,the rejection region is located under one tail (left or right)of the corresponding probability distribution,while in a two-tailed test this region is located under both tails.

Question 11

The alternative hypothesis typically agrees with the status quo.

Question 12

It is generally believed that no more than 0.50 of all babies in a town in Texas are born out of wedlock.A politician claims that the proportion of babies that are born out of wedlock is increasing.In testing the politician's claim,how does one define the population parameter of interest?

A)The current proportion of babies born out of wedlock
B)The mean number of babies born out of wedlock
C)The number of babies born out of wedlock
D)The general belief that the proportion of babies born out of wedlock is no more than 0.50

Question 13

The null hypothesis typically corresponds to a presumed default state of nature.

Question 14

In general,the null and alternative hypotheses are __________.

A)Additive
B)Correlated
C)Multiplicative
D)Mutually exclusive

Question 15

It is generally believed that no more than 0.50 of all babies in a town in Texas are born out of wedlock.A politician claims that the proportion of babies that are born out of wedlock is increasing.When testing the two hypotheses,H₀: p ≤ 0.50 and H_A: p > 0.50,p stands for _____________.

A)The current proportion of babies born out of wedlock
B)The mean number of babies born out of wedlock
C)The number of babies born out of wedlock
D)The general belief that the proportion of babies born out of wedlock is no more than 0.50

Question 16

On the basis of sample information,we either "accept the null hypothesis" or "reject the null hypothesis."

Question 17

A hypothesis test regarding the population mean μ is based on the sampling distribution of the sample mean .

Question 18

As a general guideline,we use the alternative hypothesis as a vehicle to establish something new,or contest the status quo,for which a corrective action may be required.

Question 19

The national average for an 8^th grade reading comprehension test is 73.A school district claims that its eighth-graders outperform the national average.In testing the school district's claim,how does one define the population parameter of interest?

A)The mean score on the 8^th grade reading comprehension test.
B)The number of 8^th graders that took the reading comprehension test.
C)The standard deviation of the score on the 8^th grade reading comprehension test.
D)The proportion of 8^th graders that scored above 73 on the reading comprehension test.

Question 20

The alternative hypothesis typically ___________.

A)Corresponds to the presumed default state of nature
B)Contests the status quo for which a corrective action may be required
C)States the probability of rejecting the null hypothesis when it is false
D)States the probability of rejecting the null hypothesis when it is true

Question 21

A professional sports organization is going to implement a test for steroids.The test gives a positive reaction in 94% of the people who have taken the steroid.However,it erroneously gives a positive reaction in 4% of the people who have not taken the steroid.What is the probability of a Type I and Type II error using the null hypothesis "the individual has not taken steroids."

A)Type I: 4%,Type II: 6%
B)Type I: 6%,Type II: 4%
C)Type I: 94%,Type II: 4%
D)Type I: 4%,Type II: 94%

Question 22

When conducting a hypothesis test concerning the population mean,and the population standard deviation is unknown,the value of the test statistic is calculated as __________.

A)
B)
C)
D)

Question 23

Which of the following represents an appropriate set of hypotheses?

A)
B)
C)
D)

Question 24

A fast-food franchise is considering building a restaurant at a busy intersection.A financial advisor determines that the site is acceptable only if,on average,more than 300 automobiles pass the location per hour.The advisor tests the following hypotheses: The consequences of committing a Type I error would be that _______________.

A)The franchiser builds on an acceptable site
B)The franchiser builds on an unacceptable site
C)The franchiser does not build on an acceptable site
D)The franchiser does not build on an unacceptable site

Question 25

Which of the following answers represents the objective of a hypothesis test?

A)Rejecting the null hypothesis when it is true
B)Rejecting the null hypothesis when it is false
C)Not rejecting the null hypothesis when it is true
D)B and C

Question 26

For a given sample size n,________________.

A)Decreasing the probability of a Type I error α will increase the probability of a Type II error β
B)Decreasing the probability of a Type I error α will decrease the probability of a Type II error β
C)Changing the probability of a Type I error α will have no impact on the probability of a Type II error β
D)Increasing the probability of a Type I error α will increase the probability of a Type II error β as long as σ is known

Question 27

When conducting a hypothesis test,which of the following decisions represents an error?

A)Rejecting the null hypothesis when it is true
B)Rejecting the null hypothesis when it is false
C)Not rejecting the null hypothesis when it is true
D)B and C

Question 28

When conducting a hypothesis test concerning the population mean,and the population standard deviation is known,the value of the test statistic is calculated as _________.

A)
B)
C)
D)

Question 29

A fast-food franchise is considering building a restaurant at a busy intersection.A financial advisor determines that the site is acceptable only if,on average,more than 300 automobiles pass the location per hour.If the advisor tests the hypotheses versus ,µ stands for ____________.

A)The average number of automobiles that pass the intersection per hour
B)The number of automobiles that pass the intersection per hour
C)The proportion of automobiles that pass the intersection per hour
D)The standard deviation of the number of automobiles that pass the intersection per hour

Question 30

When we reject the null hypothesis when it is actually false we have committed _________.

A)No error
B)A Type I error
C)A Type II error
D)A Type I error and a Type II error

Question 31

Many cities around the United States are installing LED streetlights,in part to combat crime by improving visibility after dusk.An urban police department claims that the proportion of crimes committed after dusk will fall below the current level of 0.84 if LED streetlights are installed.Specify the null and alternative hypotheses to test the police department's claim.

A)
B)
C)
D)

Question 32

Consider the following hypotheses that relate to the medical field: In this instance,a Type II error is often referred to as ___________.

A)A false positive
B)A false negative
C)A negative result
D)The power of the test

Question 33

A Type II error occurs when we ___________.

A)Reject the null hypothesis when it is actually true
B)Reject the null hypothesis when it is actually false
C)Do not reject the null hypothesis when it is actually true
D)Do not reject the null hypothesis when it is actually false

Question 34

When conducting a hypothesis test concerning the population proportion,the value of the test statistic is calculated as ____________.

A)
B)
C)
D)

Question 35

A hypothesis test regarding the population mean is based on _____________.

A)The sampling distribution of the sample mean
B)The sampling distribution of the sample variance
C)The sampling distribution of the sample proportion
D)The sampling distribution of the sample standard deviation

Question 36

Consider the following hypotheses that relate to the medical field: In this instance,a Type I error is often referred to as ___________.

A)A false positive
B)A false negative
C)A negative result
D)The power of the test

Question 37

A statistics professor works tirelessly to catch students cheating on his exams.He has particular routes for his teaching assistants to patrol,an elevated chair to ensure an unobstructed view of all students,and even a video recording of the exam in case additional evidence needs to be collected.He estimates that he catches 95% of students who cheat in his class,but 1% of the time he accuses a student of cheating and he is actually incorrect.Consider the null hypothesis,"the student is not cheating." What is the probability of a Type I error?

A)1%
B)5%
C)95%
D)99%

Question 38

A fast-food franchise is considering building a restaurant at a busy intersection.A financial advisor determines that the site is acceptable only if,on average,more than 300 automobiles pass the location per hour.The advisor tests the following hypotheses: The consequences of committing a Type II error would be that _______________.

A)The franchiser builds on an acceptable site
B)The franchiser builds on an unacceptable site
C)The franchiser does not build on an acceptable site
D)The franchiser does not build on an unacceptable site

Question 39

If the chosen significance level is ,then ______________.

A)There is a 5% probability of rejecting a true null hypothesis
B)There is a 5% probability of accepting a true null hypothesis
C)There is a 5% probability of rejecting a false null hypothesis
D)There is a 5% probability of accepting a false null hypothesis

Question 40

A Type I error occurs when we ___________.

A)Reject the null hypothesis when it is actually true
B)Reject the null hypothesis when it is actually false
C)Do not reject the null hypothesis when it is actually true
D)Do not reject the null hypothesis when it is actually false

Question 41

If the p-value for a hypothesis test is 0.027 and the chosen level of significance is ,then the correct conclusion is to ________________.

A)Reject the null hypothesis
B)Not reject the null hypothesis
C)Reject the null hypothesis if
D)Not reject the null hypothesis if

Question 42

Which of the following are one-tailed tests?

A)
B)
C)
D)Both A and C

Question 43

Exhibit 9-1.A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50.A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60.The population standard deviation is assumed to equal 0.40. Refer to Exhibit 9-1.At a 5% significance level,the decision is to _____________.

A)Reject H₀;we can conclude that the mean GPA is significantly greater than 3.50
B)Reject H₀;we cannot conclude that the mean GPA is significantly greater than 3.50
C)Do not reject H₀;we can conclude that the mean GPA is significantly greater than 3.50
D)Do not reject H₀;we cannot conclude that the mean GPA is significantly greater than 3.50

Question 44

A two-tailed hypothesis test of the population mean or population proportion has ________.

A)Only one critical value
B)Two critical values,both positive
C)Two critical values,both negative
D)Two critical values,one positive and one negative

Question 45

If the p-value for a hypothesis test is 0.07 and the chosen level of significance is ,then the correct conclusion is to ____________________.

A)Reject the null hypothesis
B)Not reject the null hypothesis
C)Reject the null hypothesis if
D)Not reject the null hypothesis if

Question 46

Exhibit 9-1.A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50.A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60.The population standard deviation is assumed to equal 0.40. Refer to Exhibit 9-1.In order to establish whether the mean GPA exceeds 3.50,the appropriate hypotheses are ______________.

A)
B)
C)
D)

Question 47

Exhibit 9-2.The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350. Refer to Exhibit 9-2.In order to determine whether there has been a decrease in the average number of customers visiting the dealership daily,the appropriate hypotheses are _________.

A)
B)
C)
D)

Question 48

Consider the following competing hypotheses: .The value of the test statistic is z = -1.38.If we choose a 5% significance level,then we ______________.

A)Reject the null hypothesis and conclude that the population mean is significantly different from zero
B)Reject the null hypothesis and conclude that the population mean is not significantly different from zero
C)Do not reject the null hypothesis and conclude that the population mean is significantly different from zero
D)Do not reject the null hypothesis and conclude that the population mean is not significantly different from zero

Question 49

A one-tailed hypothesis test of the population mean has ______________.

A)Only one critical value
B)Two critical values,both positive
C)Two critical values,both negative
D)Two critical values,one positive and one negative

Question 50

Exhibit 9-2.The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350. Refer to Exhibit 9-2.At a 5% significance level,the critical value(s)is (are)___________.

A)1.645
B)-1.645
C)-1.96 and 1.96
D)-2.030 and 2.030

Question 51

If the null hypothesis is rejected at a 1% significance level,then _____________.

A)The null hypothesis will be rejected at a 5% significance level
B)The alternative hypothesis will be rejected at a 5% significance level
C)The null hypothesis will not be rejected at a 5% significance level
D)The alternative hypothesis will not be rejected at a 5% significance level

Question 52

Exhibit 9-1.A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50.A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60.The population standard deviation is assumed to equal 0.40. Refer to Exhibit 9-1.At a 5% significance level,the critical value(s)is (are)________.

A)1.645
B)1.690
C)-1.96 and 1.96
D)-2.030 and 2.030

Question 53

Exhibit 9-1.A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50.A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60.The population standard deviation is assumed to equal 0.40. Refer to Exhibit 9-1.The value of the test statistic is ____________.

A)
B)
C)
D)

Question 54

Exhibit 9-1.A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 3.50.A sample of 36 honors students is taken and is found to have a mean GPA equal to 3.60.The population standard deviation is assumed to equal 0.40. Refer to Exhibit 9-1.The parameter to be tested is ____________.

A)The mean GPA of all university students
B)The mean GPA of the university honors students
C)The mean GPA of 3.60 for the 36 selected honors students
D)The proportion of honors students with a GPA exceeding 3.50

Question 55

Exhibit 9-2.The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350. Refer to Exhibit 9-2.The value of the test statistic is ____________.

A)
B)
C)
D)

Question 56

What is the decision rule when using the p-value approach to hypothesis testing?

A)Reject H₀ if the p-value > α.
B)Reject H₀ if the p-value < α.
C)Do not reject H₀ if the p-value < 1 - α.
D)Do not reject H₀ if the p-value > 1 - α.

Question 57

Exhibit 9-2.The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350. Refer to Exhibit 9-2.The population parameter to be tested is ___________.

A)The average number of 750 customers per day
B)The proportion of customers visiting the dealership per day
C)The mean number of customers visiting the dealership per day
D)The standard deviation of the number of customers visiting the dealership per day

Question 58

When conducting a hypothesis test for a given sample size,if is increased from 0.05 to 0.10,then __________________.

A)The probability of incorrectly rejecting the null increases
B)The probability of incorrectly failing to reject the null decreases
C)The probability of Type II error decreases
D)All of the above are correct

Question 59

Which of the following are two-tailed tests?

A)
B)
C)
D)Both A and C

Question 60

When conducting a hypothesis test for a given sample size,if the probability of a Type I error decreases,then the _____________.

A)Probability of Type II error decreases
B)Probability of incorrectly rejecting the null increases
C)Probability of incorrectly accepting the null increases
D)Probability of incorrectly accepting the null decreases

Question 61

Exhibit 9-2.The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350. Refer to Exhibit 9-2.At the 5% significance level,the decision is to ___________.

A)Reject H₀;we can conclude that the mean number of customers visiting the dealership is significantly less than 800
B)Reject H₀;we cannot conclude that the mean number of customers visiting the dealership is significantly less than 800
C)Do not reject H₀;we can conclude that the mean number of customers visiting the dealership is significantly less than 800
D)Do not reject H₀;we cannot conclude that the mean number of customers visiting the dealership is significantly less than 800

Question 62

Exhibit 9-4.A school teacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. Refer to Exhibit 9-4.In order to test whether the average level of radon gas is greater than the safe level,the appropriate hypotheses are ____________.

A)
B)
C)
D)

Question 63

Exhibit 9-4.A school teacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. Refer to Exhibit 9-4.At a 5% significance level,the decision is to ___________.

A)Reject we can conclude that the mean concentration of radon gas is greater than the safe level
B)Reject H₀;we cannot conclude that the mean concentration of radon gas is greater than the safe level
C)Do not reject H₀;we can conclude that the mean concentration of radon gas is greater than the safe level
D)Do not reject H₀;we cannot conclude that the mean concentration of radon gas is greater than the safe level

Question 64

A car dealer who sells only late-model luxury cars recently hired a new salesman and believes that this salesman is selling at lower markups.He knows that the long-run average markup in his lot is $5600.He takes a random sample of 16 of the new salesman's sales and finds an average markup of $5000 and a standard deviation of $800.Assume the markups are normally distributed.What is the value of an appropriate test statistic for the car dealer to use to test his claim?

A)
B)
C)
D)

Question 65

An analyst conducts a hypothesis test to check whether the mean return for a particular fund differs from 10%.He assumes that returns are normally distributed and sets up the following competing hypotheses: Over the past 10 years the fund has had an average annual return of 13.4% with a standard deviation of 2.6%.The value of the test statistic is 4.14 and the critical values at the 5% significance level are -2.262 and 2.262.The correct decision is to __________.

A)Reject H₀;we can conclude that the mean differs from 10%
B)Reject H₀;we cannot conclude that the mean differs from 10%
C)Do not reject H₀;we can conclude that the mean differs from 10%
D)Do not reject H₀;we cannot conclude that the mean differs from 10%

Question 66

In order to test if the mean IQ of employees in an organization is greater than 100,a sample of 30 employees is taken and the value of the test statistic is computed as .If we choose a 5% significance level,we _____________.

A)Reject the null hypothesis and conclude that the mean IQ is greater than 100
B)Reject the null hypothesis and conclude that the mean IQ is not greater than 100
C)Do not reject the null hypothesis and conclude that the mean IQ is greater than 100
D)Do not reject the null hypothesis and conclude that the mean IQ is not greater than 100

Question 67

A newly hired basketball coach promised a high-paced attack that will put more points on the board than the team's previously tepid offense historically managed.After a few months,the team owner looks at the data to test the coach's claim.He takes a sample of 36 of the team's games under the new coach and finds that they score an average of 101 points with a standard deviation of 6 points.Over the past 10 years,the team had averaged 99 points.What is (are)the appropriate critical value(s)to test the new coach's claim at the 1% significance level?

A)-2.438
B)-2.438 and 2.438
C)2.326
D)2.438

Question 68

Exhibit 9-3.The Boston public school district has had difficulty maintaining on-time bus service for its students ("A Year Later,School Buses Still Late," Boston Globe,October 5,2011).Suppose the district develops a new bus schedule to help combat chronic lateness on a particularly woeful route.Historically,the bus service on the route has been,on average,12 minutes late.After the schedule adjustment,the first 36 runs were an average of 8 minutes late.As a result,the Boston public school district claimed that the schedule adjustment was an improvement-students were not as late.Assume a population standard deviation for bus arrival time of 12 minutes. Refer to Exhibit 9-3.Calculate the value of the test statistic.

A)
B)
C)
D)

Question 69

In order to test if the mean returns on a major index have changed from the historic monthly average of 1.2%,a sample of 36 recent monthly returns is used to calculate the value of the relevant test statistic.At the 5% level of significance,we reject the null hypothesis if this value is ____________.

A)Greater than 1.69
B)Greater than 1.645
C)Greater than 1.96 or less than -1.96
D)Greater than 2.03 or less than -2.03

Question 70

Exhibit 9-3.The Boston public school district has had difficulty maintaining on-time bus service for its students ("A Year Later,School Buses Still Late," Boston Globe,October 5,2011).Suppose the district develops a new bus schedule to help combat chronic lateness on a particularly woeful route.Historically,the bus service on the route has been,on average,12 minutes late.After the schedule adjustment,the first 36 runs were an average of 8 minutes late.As a result,the Boston public school district claimed that the schedule adjustment was an improvement-students were not as late.Assume a population standard deviation for bus arrival time of 12 minutes. Refer to Exhibit 9-3.At the 1% significance level,does the evidence support the Boston Public Schools' claim?

A)No,since the p-value is greater than α.
B)Yes,since the p-value is greater than α.
C)No,since the value of the test statistic is less than the critical value.
D)Yes,since the value of the test statistic is less than the critical value.

Question 71

A temp agency feels that one of its recruiters has unorthodox methods and claims that the wages the recruiter secures for its temps differs from the agency's average wage of $12 per hour.The agency takes a random sample of 49 recent contracts the recruiter secured and finds an average wage of $11.25 per hour and a standard deviation of $2.25 per hour.Does the evidence support the agency's claim at the 5% significance level?

A)Yes,since the p-value is greater than α,the claim is supported.
B)No,since the p-value is not greater than α,the claim is not supported.
C)Yes,since the value of the test statistic is less than the critical value,the claim is supported.
D)No,since the value of the test statistic is greater than the critical value,the claim is not supporteD.

Question 72

Exhibit 9-3.The Boston public school district has had difficulty maintaining on-time bus service for its students ("A Year Later,School Buses Still Late," Boston Globe,October 5,2011).Suppose the district develops a new bus schedule to help combat chronic lateness on a particularly woeful route.Historically,the bus service on the route has been,on average,12 minutes late.After the schedule adjustment,the first 36 runs were an average of 8 minutes late.As a result,the Boston public school district claimed that the schedule adjustment was an improvement-students were not as late.Assume a population standard deviation for bus arrival time of 12 minutes. Refer to Exhibit 9-3.Develop the null and alternative hypotheses to determine whether the schedule adjustment reduced the average lateness time of 12 minutes.

A)
B)
C)
D)

Question 73

Exhibit 9-4.A school teacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. Refer to Exhibit 9-4.At a 5% significance level,the critical value(s)is (are)_______.

A)-1.690
B)1.690
C)-1.96 and 1.96
D)-2.030 and 2.030

Question 74

A 99% confidence interval for the population mean yields the following results: [-3.79,5.86].At the 1% significance level,what decision should be made regarding a hypothesis test with hypotheses ?

A)Reject H₀;we can conclude that the mean differs from zero.
B)Reject H₀;we cannot conclude that the mean differs from zero.
C)Do not reject H₀;we can conclude that the mean differs from zero.
D)Do not reject H₀;we cannot conclude that the mean differs from zero.

Question 75

A recent report claimed that Americans are retiring later in life (U.S.News & World Report,August 17,2011).An economist wishes to determine if the mean retirement age has increased from 62.To conduct the relevant test,she takes a random sample of 38 Americans who have recently retired and computes the value of the test statistic as .With a = 0.05,she ___________________.

A)Rejects the null hypothesis and concludes that the mean retirement age has increased
B)Rejects the null hypothesis and concludes that the mean retirement age has not increased
C)Does not reject the null hypothesis and does not conclude that the mean retirement age has changed
D)Does not reject the null hypothesis and does not conclude that the mean retirement age has increased

Question 76

A newly hired basketball coach promised a high-paced attack that will put more points on the board than the team's previously tepid offense historically managed.After a few months,the team owner looks at the data to test the coach's claim.He takes a sample of 36 of the team's games under the new coach and finds that they score an average of 101 points with a standard deviation of 6 points.Over the past 10 years,the team had averaged 99 points.What is the value of the appropriate test statistic to test the new coach's claim at the 1% significance level?

A)
B)
C)
D)

Question 77

Exhibit 9-4.A school teacher is worried that the concentration of dangerous,cancer-causing radon gas in her classroom is greater than the safe level of 4pCi/L.The school samples the air for 36 days and finds an average concentration of 4.4pCi/L with a standard deviation of 1pCi/L. Refer to Exhibit 9-4.The value of the test statistic is ___________.

A)
B)
C)
D)

Question 78

Exhibit 9-3.The Boston public school district has had difficulty maintaining on-time bus service for its students ("A Year Later,School Buses Still Late," Boston Globe,October 5,2011).Suppose the district develops a new bus schedule to help combat chronic lateness on a particularly woeful route.Historically,the bus service on the route has been,on average,12 minutes late.After the schedule adjustment,the first 36 runs were an average of 8 minutes late.As a result,the Boston public school district claimed that the schedule adjustment was an improvement-students were not as late.Assume a population standard deviation for bus arrival time of 12 minutes. Refer to Exhibit 9-3.At the 5% significance level,does the evidence support the Boston public school district's claim?

A)No,since the p-value is less than α.
B)Yes,since the p-value is less than α.
C)No,since the value of the test statistic is greater than the critical value.
D)Yes,since the value of the test statistic is greater than the critical value.

Question 79

You want to test if more than 20% of homes in a neighborhood have recently been sold through a short sale,at a foreclosure auction,or by the bank following an unsuccessful foreclosure auction.You take a sample of 60 homes from this neighborhood and find that 14 fit your criteria.The appropriate null and alternative hypotheses are ___________.

A)
B)
C)
D)

Question 80

What type of data would necessitate using a hypothesis test of the population proportion rather than a test of the population mean?

A)Ratio
B)Interval
C)Qualitative
D)Quantitative