Question 16

In a hypothesis test, the claim is 25 while the sample of 34 has a mean of 21 and a standard deviation of 5.9. In this hypothesis test, would a z test statistic be used or a t test statistic and why?

A)t test statistic would be used as the sample size is less than 30

B)z test statistic would be used as the mean is greater than 30

C)t test statistic would be used as the standard deviation is less than 10

D)z test statistic would be used as the sample size is greater than 30

Question 17

A university claims that the mean time professors are in their offices for students is at least 6.5 hours each week. A random sample of eight professors finds that the mean time in their offices is 6.2 hours each week. With a population standard deviation of 0.49 hours, can the university's claim be supported at =0.05?

A)No, since the test statistic is not in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported

B)No, since the test statistic is in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported

C)Yes, since the test statistic is not in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported

D)Yes, since the test statistic is in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported

Question 18

A credit reporting agency claims that the mean credit card debt in a town is greater than $3500. A random sample of the credit card debt of 20 residents in that town has a mean credit card debt of $3600 and a standard deviation of $391. At =0.10, can the credit agency's claim be supported?

A)No, since p-value of 0.13 is greater than 0.10, reject the null. Claim is null, so is not supported

B)Yes, since p-value of 0.13 is greater than 0.10, fail to reject the null. Claim is null, so is supported

C)Yes, since p-value of 0.13 is less than 0.55, reject the null. Claim is alternative, so is supported

D)No, since p of 0.13 is greater than 0.10, fail to reject the null. Claim is alternative, so is not supported

Question 19

A car company claims that its cars achieve an average gas mileage of at least 26 miles per gallon. A random sample of eight cars from this company have an average gas mileage of 25.5 miles per gallon and a standard deviation of 1 mile per gallon. At =0.06, can the company's claim be supported?

A)Yes, since the test statistic of -1.41 is not in the rejection region defined by the critical value of -1.55, the null is rejected. The claim is the null, so is supported

B)No, since the test statistic of -1.41 is in the rejection region defined by the the critical value of -1.77, the null is rejected. The claim is the null, so is not supported

C)Yes, since the test statistic of -1.41 is not in the rejection region defined by the critical value of -1.77, the null is not rejected. The claim is the null, so is supported

D)No, since the test statistic of -1.41 is close to the critical value of -1.24, the null is not rejected. The claim is the null, so is supported

Question 20

A researcher wants to determine if extra homework problems help 8th

grade students learn algebra. An 8th grade class is divided into pairs and one student from each pair has extra homework problems and the other in the pair does not. After 2 weeks, the entire class takes an algebra test and the results of the two groups are compared. To be a valid matched pair test, what should the researcher consider in creating the two groups?

A)That each pair of students has similar IQs or abilities in mathematics

B)That each pair of students has similar ages at the time of the testing

C)That the group without extra homework problems receives different instruction

D)That the group with the extra homework problems has fewer after school activities