See Table E11-1 for data on the ratings of quarterbacks for the 2008 National Football League season (The Sports Network). It is suspected that the rating (y) is related to the average number of yards gained per pass attempt (x).

(a) Calculate the least squares estimates of the slope and intercept. What is the estimate of σ2? Graph the regression model.

(b) Find an estimate of the mean rating if a quarterback averages 7.5 yards per attempt.

(c) What change in the mean rating is associated with a decrease of one yard per attempt?

(d) To increase the mean rating by 10 points, how much increase in the average yards per attempt must be generated?

(e) Given that x = 7.21 yards, find the fitted value of x and the corresponding residual.

PSYCH STATS POWERPOINT 3 ● percentile is a score that is used to determine the percentile rank ● central tendency: single score chosen to represent the entire set of scores ○ defines the center of distribution ○ allows you to compare 2 sets of data ● problems… its a single score ○ no standard procedure to calculate ○ not all distributions are the same ■ some aren’t symmetrical and this makes it more difficult to determine the best value to be representative of the sample ● the mean: the average ● median: middle value ● mode: most common value Mode ● calculated by looking at the most common value ● taken straight from the scores ● best used for nominal data ● if two values occ