Data on 1,470 cars were obtained from the October 2002 issue of Road & Track: The New Cars. The following variables were available in order to predict selling price (y): (Hint: Realize that the raw data are NOT necessary in order to answer these questions and therefore are NOT provided in the HW11 Data file.) weight, in pounds (WEIGHT) mileage in city driving (CITYMPG) mileage in highway driving (HWYMPG) horsepower, @ 6300 rpm (HP) number of cylinders (CYLIN) displacement, in liters (LITER) (a) If an all possible regressions analysis is performed, how many regression models are possible?