Question

1. Exhibit 4 (Questions 19-22)

   The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a sample standard deviation of S = 4 hours. We are interested to test the following hypotheses using α = 0.05 level of significance:

   H₀ : σ² ≤ 14

   H_a : σ² > 14

   Refer to Exhibit 4. Assuming that the population of service times follows an approximately normal distribution, what is the proper test statistic?

   	A.	Chi-square distribution with 4 degrees of freedom
   	B.	Chi-square distribution with 14 degrees of freedom
   	C.	Chi-square distribution with 15 degrees of freedom
   	D.	Chi-square distribution with 16 degrees of freedom

2.5 points

Question 20

1. Exhibit 4 (Questions 19-22)

   The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a sample standard deviation of S = 4 hours. We are interested to test the following hypotheses using α = 0.05 level of significance:

   H₀ : σ² ≤ 14

   H_a : σ² > 14

   Refer to Exhibit 4. Assuming that the population of service times follows an approximately normal distribution, what is the value of the test statistic?

   	A.	4
   	B.	14
   	C.	15
   	D.	16

2.5 points

Question 21

1. Exhibit 4 (Questions 19-22)

   The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a sample standard deviation of S = 4 hours. We are interested to test the following hypotheses using α = 0.05 level of significance:

   H₀ : σ² ≤ 14

   H_a : σ² > 14

   Refer to Exhibit 4. Assuming that the population of service times follows an approximately normal distribution, what is the p-value?

   	A.	More than 0.10
   	B.	Between 0.05 and 0.10
   	C.	Less than 0.01
   	D.	between 0.025 and 0.05

2.5 points

Question 22

1. Exhibit 4 (Questions 19-22)

   The manager of the service department of a local car dealership has noted that the service times of a sample of 15 new automobiles has a sample standard deviation of S = 4 hours. We are interested to test the following hypotheses using α = 0.05 level of significance:

   H₀ : σ² ≤ 14

   H_a : σ² > 14

   Refer to Exhibit 4. Assuming that the population of service times follows an approximately normal distribution, what is the conclusion?

   	A.	Reject the null hypothesis at α = 0.05 . The sample supports the alternative hypothesis that the population variance of the service times exceeds 14.
   	B.	We cannot reject the null hypothesis at α = 0.05 . The sample does not support the alternative hypothesis that the population variance of the service times exceeds 14.
   	C.	We can reject the null hypothesis only if the level of significance, α, is reduced from 0.05 to 0.01.
   	D.	The test is inconclusive.

Answer 1