Based on a sample of n = 20, the least squares method was used to develop the following prediction line: ŷi = 5 + 3Xi. In addition,
a. Construct a 95% confidence interval estimate of the population mean response for X = 4.
b. Construct a 95% prediction interval of an individual response for X = 4.
c. Compare the results of (a) and (b) with those of Problem 12.55 (a) and (b). Which intervals are wider? Why?