[EX03-073] Baseball teams win and lose games. Many fans believe that a team’s earned run average (ERA) has a major effect on winning. During the 2004 season, the 30 major league baseball teams recorded the following number of wins while generating these ERAs.

Wins ERA Wins ERA Wins ERA 96 3.74 98 4.18 63 4.76 105 3.75 67 4.24 80 4.81 89 3.81 92 4.28 70 4.81 93 4.01 72 4.29 83 4.91 92 4.03 91 4.29 67 4.91 87 4.03 67 4.33 72 4.93 92 4.05 86 4.45 51 4.98 71 4.09 89 4.53 58 5.15 83 4.10 101 4.69 76 5.19 91 4.17 78 4.70 68 5.54 Source: http://mlb.mlb.com

a. Do you think the teams with the better ERAs have the most wins? (The lower the ERA, the fewer earned runs the other team scored.)

b. If this is true, what will the pattern on the scatter diagram look like? Be specific.

c. Construct a scatter diagram of these data.

d. Does the scatter diagram suggest that teams tend to win more games when their team ERA is lower? Explain.

e. Calculate the line of best fit using x  ERA and y  number of wins.

f. On the average, how is the number of wins affected by an increase of 1 in the ERA? Explain how you determined this number.

g. Do your findings seem to support the idea that the teams with the better ERAs will have the most wins? Justify your response.