Consider the data and simple linear regression model in Exercise 6-6.
(a) Find the mean rise in blood pressure given that the sound pressure level is 85 decibels.
(b) Compute a 99% CI on this mean response.
(c) Compute a 99% PI on a future observation when the sound pressure level is 85 decibels.
(d) What do you notice about the relative size of these two intervals? Which is wider and why?