In exercise 5, the owner of Showtime Movie Theaters, Inc., used multiple regression analysis to predict gross revenue (y) as a function of television advertising (x1) and newspaper advertising (x2). The estimated regression equation was
 = 83.2 + 2.29x1 + 1.30x2
The computer solution provided SST = 25.5 and SSR = 23.435.
a. Compute and interpret R2 and R2a.
b. when television advertising was the only independent variable, R2 = .653 and R2a = .595. Do you prefer the multiple regression results? Explain.