Representing a large auto dealer, a buyer attends car auctions. To help with the bidding, the buyer built a regression equation to predict the resale value of cars purchased at the auction. The...

Representing a large auto dealer, a buyer attends car auctions. To help with the bidding, the buyer built a regression equation to predict the resale value of cars purchased at the auction. The equation is

(a) Which is more predictable: the resale value of one five-year-old car, or the average resale value of a collection of 25 cars, all of which are five years old?

(b) According to the buyer’s equation, what is the estimated resale value of a five-year-old car? The average resale value of a collection of 25 cars, each five years old?

(c) Could the prediction from this equation overestimate or underestimate the resale price of a car by more than $2,500?

You do it

For each data table, before answering the questions, determine whether the simple regression model is a reasonable description of the association between the two indicated variables. In particular, consider the conditions needed for the reliable use of the SRM. Then answer the listed questions.