FILE Is it defense or offense that wins football games?

Consider the following data, which include a team's winning record (Win), the average number of yards made, and the average number of yards allowed during the 2009 NFL season. The complete data, labeled Football, can be found on the text website.

Team Win (%) Yards Made Yards Allowed Arizona Cardinals 62.50 344.40 346.40 Atlanta Falcons 56.30 340.40 348.90 Washington Redskins 25.00 312.50 319.70 SOURCE: NFL w e b s ite .

a. Compare two simple linear regression models, where Model 1 predicts winning percentage based on Yards Made and Model 2 uses Yards Allowed.

b. Estimate a multiple regression model, Model 3, that applies both Yards Made and Yards Allowed to forecast winning percentage. Is this model an improvement over the other two models? Explain.