As indicated in the chapter-opening vignette, the National Football League quarterback passer rating is somewhat of a mystery to most observers. Data file XR17073 includes the passer rating for 32 NFL quarterbacks during the 2008 season, along with these ten performance measurements for each quarterback: passing attempts, completions, completion percentage, yards gained, average yards per attempt, number of touchdowns, percentage of passes that were touchdowns, longest pass completed, number of interceptions, and percentage of passes that were intercepted. With passer rating as the dependent variable, use stepwise regression to find out which predictor variables are especially important in determining the passer rating. Comment on the results, including the percentage of the variation in passer ratings that is explained by the model.
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