Here is the data we are working with:

Team League Team Salary

Arizona National 65.80

Atlanta National 89.60

Baltimore American 118.90

Boston American 168.70

Chicago Cubs National 117.20

Chicago White Sox American 110.70

Cincinnati National 117.70

Cleveland American 87.70

Colorado National 98.30

Detroit American 172.80

Houston American 69.10

Kansas City American 112.90

LA Angels American 146.40

LA Dodgers National 230.40

Miami National 84.60

Milwaukee National 98.70

Minnesota American 108.30

NY Mets National 100.10

NY Yankees American 213.50

Oakland American 80.80

Philadelphia National 133.00

Pittsburgh National 85.90

San Diego National 126.60

San Francisco National 166.50

Seattle American 123.20

St. Louis National 120.30

Tampa Bay American 74.80

Texas American 144.80

Toronto American 116.40

Washington National 174.50

Here are the questions:

Refer to the Baseball 2016 data, which report information on the 30 Major League Baseball teams for the 2016 season.

a. At the .05 significance level, can we conclude that there is a difference in the mean salary of teams in the American League versus teams in the National League?

I calculated the mean for the American League as 123.2667 and the standard deviation as 40.1476.

I calculated the mean for the National League as 120.6133 and the standard deviation as 42.3751.

The next calculation confuses me. I subtract 123.27-120.61 / square root of 40.15/15 + 42.38/15....is this correct?

I get lost from here and with the p value. Can you help explain the next steps?