Car mileage and weight The Car Weight and Mileage data file on the text CD shows
ID: 3261909 • Letter: C
Question
Car mileage and weight The Car Weight and Mileage data file on the text CD shows the weight (in pounds) and mileage (miles per gallon) of 25 different model autos.
a. Identify the natural response variable and explanatory variable.
b. The regression of mileage on weight has MINITAB regression output
State the prediction equation and report the y-intercept and slope.
c. Interpret the slope in terms of a 1000-pound increase in the vehicle weight.
d. Does the y-intercept have any contextual meaning for these data? (Hint: The weight values range between 2460 and 6400 pounds.)
Explanation / Answer
Answer to the question is as follows:
a. The natural response variable is Car Mileage. The explanatory variable is the Car Weight
b. Prediction Equation is : 45.645 -.0052220*Weight = Car Mileage
The intercept is 45.645
The slope is -.0052220
c. For a 1000 pound increase in the vehicle weight the , the Mileage decreases by 1000(-.0052220) = 5.22 units
d. When the weight of car is 9, then the mileage is 45.645, this doesnt make any contextual sense. Since weight is zero,
meaning there is no car, hence a there is no meaning of a mileage to such a car ( As it doesn't exist). A normal car( as
given in the question will weight from 2460 to 6400 pounds)