American League baseball teams play their games with the designated hitter rule, meaning that pitchers do not bat. The league believes that replacing the pitcher, traditionally a weak hitter, with another player in the batting order produces more runs and generates more interest among fans. The data provided in the file on the CD include the average numbers of runs scored per game (Runs per game) by American League and National League teams for the 2012 season (www.baseball-reference.com).

a) Create an appropriate display of these data. What do you see?
b) With a 95% confidence interval, estimate the mean number of runs scored by American League teams.
c) With a 95% confidence interval, estimate the mean number of runs scored by National League teams.
d) Explain why you should not use two separate confidence intervals to decide whether the two leagues differ in average number of runs scored.

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American League National League R/G HR Los Angeles Anls4.73 87 Colorado Rockies 4.68 166 Texas Rangers 4.99 200 St. Louis Cardinals 4.72 159 Detroit Tigers 4.48 163 San Francisco Giats 443 103 Kansas City Royals 4.7 131 Washington Nationals 194 New York Yankees 496 245 Milwaukee Brers4.79 202 Boston Red Sx 43 65Arizona Diamondbacks 453 165 Minnesota Tw 43 131 Philadelphia Plis 422 158 Chicago White Sox 4.62 211 Los Angeles Dodgrs 3.116 4.13 172 4.01 139 432 149 Tampa Bay Rays 430 75 San Diego Padres 4.02 121 3.76 137 Seattle Mariners 382 149 Pittsburgh Piars 4.02 170 3.78 137 3.60 146 Team R/G HR Team Cleveland Indians 4.12 136 Cincinnati Reds Baltimore Orioles 440 214New York Mets Toronto Blue Jays 4.42 98 Atlanta Braves Oakland Athletics 4.40 95 Miami Marlins Chicago Cubs Houston Astros