In order to control costs, a company wishes to study the amount of money its sales force spends entertaining clients ...

     In order to control   costs, a company wishes to study the amount of money its sales force spends   entertaining clients. The following is a random sample of six entertainment   expenses (dinner costs for four people) from expense reports submitted by   members of the sales force. $157 $132 $109 $145 $125 $139 _ 2 2 a) Calculate   x , s, and s for the expense data. b) Assuming that the distribution of   entertainment expenses is approximately normally distributed, calculate   estimates of tolerance intervals containing 68.26 percent, 95.44 percent, and   99.473 percent of all entertainment expenses by the sales force. c) If a   member of the sales force submits an entertainment expense (dinner cost for   four) of $190 should this expense be considered unusually high (and possibly   worthy of investigation by the company? Explain your answer. d) Compute and   interpret the z-score for each of the six entertainment expenses.