Energy use: Use the data in Exercise 7 for the following.

a. Compute a point estimate for the mean energy use for families with an income of $50,000.

b. Construct a 95% confidence interval for the mean energy use for families with an income of $50,000.

c. Predict the energy use for a particular family with an income of

$50,000.

d. Construct a 95% prediction interval for the energy use for a particular family with an income of $50,000.