The statistical significance of changes to R2 depends on the number of variables added to the model. In these examples, the current regression has four explanatory variables with R2 = 0.60 and has been fit to n = 75 observations.
(a) Is an increase to R2 = 0.61 by adding one vari- able statistically significant? Why or why not?
(b) Is an increase to R2 = 0.64 by adding four vari- ables statistically significant? Why or why not?