Predicting Winning Percentage for the NFL The National Football League (NFL) records a variety of performance data for individuals and teams (NFL website). Some of the year-end performance data for the 2005 season appear in the file named NFLStats. Each row of the data set corresponds to an NFL team, and the teams are ranked by winning percentage. Descriptions for the data follow: WinPct Percentage of games won DefYds/G Average number of yards per game given up on defense RushYds/G Average number of rushing yards per game PassYds/G Average number of passing yards per game FGPct Percentage of field goals made TakeInt Takeaway interceptions; the total number of interceptions made by the team’s defense TakeFum Takeaway fumbles; the total number of fumbles recovered by the team’s defense GiveInt Giveaway interceptions; the total number of interceptions thrown by the team’s offense GiveFum Giveaway fumbles; the total number of fumbles recovered by the team’s offense Managerial Report 1. Use methods of descriptive statistics to summarize the data. Comment on the findings. 2. Develop an estimated regression equation that can be used to predict WinPct using DefYds/G, RushYds/G, PassYds/G, and FGPct. Discuss your findings. 3. Starting with the estimated regression equation developed in part (2), delete any independent variables that are not significant and develop a new estimated regression equation that can be used to predict WinPct. Use α = .05. 4. Some football analysts believe that turnovers are one of the most important factors in determining a team’s success. With Takeways = TakeInt + TakeFum and Giveawasys = GiveInt + GiveFum, let NetDiff = Takeaways – Giveaways. Develop an estimated regression equation that can be used to predict WinPct using NetDiff. Compare your results with the estimated regression equation developed in part (3). 5. Develop an estimated regression equation that can be used to predict WinPct using all the data provided.