You used radio advertising and newspaper advertising to predict sales (stored in Advertise). Develop a regression model to predict sales that includes radio advertising, newspaper advertising, and the interaction of radio advertising and newspaper advertising.
a. At the 0.05 level of significance, is there evidence that the interaction term makes a significant contribution to the model?
b. Which regression model is more appropriate, the one used in this problem or the one used in Problem 14.6? Explain.
For Information: Problem 14.6