Suppose the time it takes college students to complete their

Suppose the time it takes college students to complete their degree follows a Normal distribution with mean and standard deviation = 1.2 years. Based on a random sample of college students, you construct a 95% confidence interval for and find it to be 1.26 ± 0.08 years. Which of the following is true?

A) H₀ of a test of the hypotheses H₀ : m = 1.2, H_a : m 1.2 would be rejected at the 0.05 level.

B) H₀ of a test of the hypotheses H₀ : m = 1.1, H_a : m 1.1 would be rejected at the 0.05 level.

C) H₀ of a test of the hypotheses H₀ : m = 1.3, H_a : m 1.3 would be rejected at the 0.05 level.

D) All the above

Solution

B) is true

Reason:

As m=1.1 is beyond the range of the confidence interval(1.18-1.34), we can safely reject the null hypothesis at the 0.05 level.

1.2 and 1.3 are both in the confidence interval