At Oxnard University, a sample of 18 senior accounting majors showed a mean cumulative GPA of 3.35 with a standard deviation of 0.25.
(a) At α = .05 in a two-tailed test, does this differ significantly from 3.25 (the mean GPA for all business school seniors at the university)?
(b) Use the sample to construct a 95 percent confidence interval for the mean. Does the confidence interval include 3.25?
(c) Explain how the hypothesis test and confidence interval are equivalent.