Refer to Exercise 2 in Section 8.2.
a. Using each of the three models in turn, predict the NOx emission when Speed = 1500, Torque = 400, and HP = 150.
b. Using each of the three models in turn, predict the NOx emission when Speed = 1600, Torque = 300, and HP = 100.
c. Using each of the three models in turn, predict the NOx emission when Speed = 1400, Torque = 200, and HP = 75.
d. Which model or models appear to be the best? Choose one of the answers, and explain.
i. The model with Speed and Torque as independent variables is the best.
ii. The model with Speed and HP as independent variables is the best.
iii. The model with Speed, Torque, and HP as independent variables is the best.
iv. The model with Speed and Torque and the model with Speed and HP are about equally good; both are better than the model with Speed, Torque, and HP.
v. The model with Speed and Torque and the model with Speed, Torque, and HP are about equally good; both are better than the model with Speed and HP.
vi. The model with Speed and HP and the model with Speed, Torque, and HP are about equally good; both are better than the model with Speed and Torque.
vii. All three models are about equally good.