Suppose the model ???? = ????0 +????1????1 +????2????2 +????3????3 +???? was fit to ???? = 66 observations yielding the fitted model ???? = 3.1 +

Suppose the model ???? = ????0 +????1????1 +????2????2 +????3????3 +???? was fit to ???? = 66 observations yielding the fitted model ˆ???? = −3.1 + 4.5????1 + 1.3????2 − 6.9????3.

(a) Estimate the mean value of ???? when ????1 = 3,????2 = 5, and ????3 = 1.5.

(b) If the standard error of the estimated mean of ???? is ???????? = 0.55 when ????1 = 3,????2 = 5, and ????3 = 1.5 compute a 95% confidence interval for the mean of ???? for ????1 =

3,????2 = 5, and ????3 = 1.5.

(c) Predict the value of ???? when ????1 = 3,????2 = 5, and ????3 = 1.5.

(d) If ???????? = 0.26, compute a 95% prediction interval for the value of ???? when ????1 = 3,????2 = 5, and ????3 = 1.5.