Consider the electric power consumption data in Exercise 12-6.
(a) Find 95% confidence intervals on B1, B2, B3, and B4.
(b) Find a 95% confidence interval on the mean of Y when x1 = 75, x2 = 24, x3 = 90, and x4 = 98.
(c) Find a 95% prediction interval on the power consumption when x1 = 75, x2 = 24, x3 = 90, and x4 = 98.