Refer to Problems 11 and 12.
a. Find a point estimate for the mean graduation rate of all universities that have a student-to-faculty ratio of 17.
b. Determine a 95% confidence interval for the mean graduation rate of all universities that have a student-to-faculty ratio of 17.
c. Find the predicted graduation rate for a university that has a student-to-faculty ratio of 17.
d. Find a 95% prediction interval for the graduation rate of a university that has a student-to-faculty ratio of 17.
e. Explain why the prediction interval in part (d) is wider than the confidence interval in part (b).
Presume that the variables student-to faculty ratio and graduation rate satisfy the assumptions for regression inferences.