In 2001, the Arizona Diamondbacks defeated the New York Yankees in the Baseball World Series in 7 games. Some players, such as Bautista and Finley for the Diamondbacks, had a substantially higher batting average during the World Series than during the regular season. Others, such as Brosius and Jeter for the Yankees, did substantially poorer. You set out to investigate whether or not the regular season batting average is a good indicator for the World Series batting average. The results for 11 players who had the most at bats for the two teams are:

AZWsavg_hat= -0.347 + 2.290AZSeasavg,R2= 0.11,SER= 0.145,

NYWsavg_hat = 0.134 + 0.136NYSeasavg,R2= 0.001,SER= 0.092,

whereWsavgandSeasavgindicate the batting average during the World Series and the regular season respectively.

(a) Focusing on the coefficients first, what is your interpretation?

(b) What can you say about the explanatory power of your equation? What do you conclude from this? Explain.