Exercise 11-6 presented data on y = steam usage and x = monthly average temperature.
(a) Find a 99% confidence interval for B1.
(b) Find a 99% confidence interval for B0.
(c) Find a 95% confidence interval on mean steam usage when the average temperature is 55oF.
(d) Find a 95% prediction interval on steam usage when temperature is 55oF. Explain why this interval is wider than the interval in part (c).