The Editors of a National Automotive Magazine Recently Studied 30

Multiple Choice

The editors of a national automotive magazine recently studied 30 different automobiles sold in the United States with the intent of seeing whether they could develop a multiple regression model to explain the variation in highway miles per gallon. A number of different independent variables were collected. The following regression output is the result of using a forward selection stepwise regression approach. Which of the following might explain why no other independent variables entered the model?

A) No other variable had a correlation with the dependent variable that was close to 1.0.
B) None of the remaining variables had a positive correlation with y.
C) The remaining variables must be nearly perfectly correlated with the two variables already in the model.
D) Given the two variables already in the model, none of the others could add significantly to the percentage of variation in the y variable that would be explained by the model.