1. When one of the five predictor variables in the preceding example is elimi- nated from the analysis, the value of R2 drops from 0.75 to 0.71. What does this tell us about the variable that was dropped?
2. What is multicollinearity? Why does it occur in multiple regression problems?
3. What is stepwise regression? Why is it used?
4. Discuss the regression toward the mean phenomenon. Give a simple real- life example.