Refer to Exercise 12.1. There are three modes of drive for automobiles: rear- wheel, front-wheel, and all- wheel drive. The engineer wants to relate miles per gallon for the vehicles to the three explanatory variables with a separate model for each mode of drive mechanism.
a. Write a first- order general linear model that allows for different slopes and intercepts for each mode of drive mechanism.
b. In terms of the coefficients of the model in part (a), identify the slopes and intercepts for each of the three modes of drive mechanism.
In exercise
An automotive engineer wanted to explain and predict the miles per gallon during city driving, y, for a variety of vehicles, using these explanatory variables: c, the number of cylinders; y, the interior passenger volume; and w, the weight of the vehicle.
a. Write a first- order multiple regression model relating y to c, y, and w.
b. Write a second- order multiple regression model relating y to c, y, w; the squares of c, v, w; and their cross- products.