Suppose you have four potential independent variables, x1, x2, x3, and x4, from which you want to develop a multiple regression model. Using stepwise regression, x2 and x4 entered the model.
a. Why did only two variables enter the model? Discuss.
b. Suppose a full regression with only variables x2 and x4 had been run. Would the resulting model be different from the stepwise model that included only these two variables? Discuss.
c. Now, suppose a full regression model had been developed, with all four independent variables in the model. Which would have the higher R2 value, the full regression model or the stepwise model? Discuss.