13.81 A baseball analyst would like to study various team statistics for the 2012 baseball season to determine which variables might be useful in predicting the number of wins achieved by teams during the season. He begins by using a team's earned run average (ERA), a measure of pitching performance, to predict the number of wins. He collects the team ERA and team wins for each of the 30 Major League Baseball teams and stores these data in BB2012. (Hint: First determine which are the independent and dependent variables.)
a. Assuming a linear relationship, use the least-squares method to compute the regression coefficients b0 and b1.
b. Interpret the meaning of the Y intercept, b0, and the slope, b1, in this problem.
c. Use the prediction line developed in (a) to predict the mean number of wins for a team with an ERA of 4.50.
d. Compute the coefficient of determination, r2, and interpret its meaning.