Sruti Singh (see Problem 11-33) would like to investigate the effect of adding the age of the car (in years) to the regression model. The table in Problem 11-33 includes the ages of the original 10 cars. (a) Develop a multiple regression model to predict the market value of a Volkswagen Golf based on its mileage and age.
(b) What percentage of the selling price variation is explained by this expanded model?
(c) The car that Sruti found with 46,700 miles is 5 years old. What is the revised 95% confidence interval for the market value of this car? Explain why this interval is different from the one in Problem 11-33(c).