TABLE 14-14
An automotive engineer would like to be able to predict automobile mileages. She believes that the two most important characteristics that affect mileage are horsepower and the number of cylinders (4 or 6) of a car. She believes that the appropriate model is
Y = 40 - 0.05X₁ + 20X₂ - 0.1X₁X₂
where X₁ = horsepower
X₂ = 1 if 4 cylinders, 0 if 6 cylinders
Y = mileage.
-Referring to Table 14-14, the fitted model for predicting mileages for 6-cylinder cars is ________.
A) 40 - 0.05X₁
B) 40 - 0.10X₁
C) 60 - 0.10X₁
D) 60 - 0.15X₁

Question

Quizplus · Accepted Answer

For 6-cylinder cars, X₂ = 0. Substituting X₂ = 0 into the model Y = 40 - 0.05X₁ + 20X₂ - 0.1X₁X₂ gives Y = 40 - 0.05X₁.

TABLE 14-14 An Automotive Engineer Would Like to Be Able to Predict