The manager of the food concession at a major league baseball stadium wanted to be able to predict the attendance of a game 24 hours in advance to prepare the correct amount of food for sale. He believed that the two most important factors were the home team’s winning percentage and the visiting team’s winning percentage. In order to examine his beliefs, he collected the attendance figures, the home team’s winning percentage, and the visiting team’s winning percentage for 40 randomly selected games from all the teams in the league.

a. Conduct a regression analysis using a first-order model with interaction.

b. Do these results indicate that your model is valid? Explain.