In order to determine the difference between the yearly incomes of marketing managers in the East and West of the United States, the following information was gathered.
East West
n1 = 40 n2 = 45
= 72 (in $1,000) = 78 (in $1,000)
s1 = 6 (in $1,000) s2 = 8 (in $1,000)