In order to control costs, a company wishes to study the amount of money its sales forces spends entertaining clients. The following is a random sample of six entertainment expenses (dinner costs for 4 people) from expense reports submitted by members of the sales force.
$157 $132 $109 $145 $125 $139
Calculate /x, s^2, and s for the expense data. In addition, show that the two different formulas for calculating s^2 give the same result.