Use the salaries model based on years of postsecondary education and age to make a 95% confidence

Question:

Use the salaries model based on years of postsecondary education and age to make a 95% confidence interval estimate of the average salary for individuals who are 35 years old and have five years of postsecondary education. Do you expect this confidence interval to be wider or narrower than the prediction interval estimate from Exercise 18? Why?