An engineer wants to determine how the weight of a car, x, affects gas mileage, y. The following data represent the weight of various cars and their miles per hour. Car A B C D E
Wegoht(pounds), x 2665 2925 3450 3830 4125
Miles per gallon, y 26.6 20.8 17.6 19.7 14

Required:
a. Find the least-squares regression line treating weight as the explanatory variable and miles per gallon as the response variable.

b. Interpret the slope and intercept, if appropriate. Choose the best interpretation for the slope.
1. The slope indicates the average miles per gallon.
2. The slope indicates the average change in miles per gallon for an increase of 1 pound in weight.
3. The slope indicates the ratio between the average weight and the average miles per gallon.
4. The slope indicates the average weight.
5. It is not appropriate to interpret the slope because it is not equal to zero.

Choose the best interpretation for the y-intercept.

1. The y-intercept indicates the miles per gallon for a new car.
2. The y-intercept indicates the average weight for the population.
3. The y-intercept indicates the miles per gallon of the lightest car in the population.
4. The y-intercept indicates the average miles per gallon for the population.
5. It is not appropriate to interpret the y-intercept because it is outside the scope of the model.