dolution

An automobile manufacturer employs sales representatives who make calls on dealers. The manufacturer wishes to compare the effectiveness of four different call-frequency plans for the sales representatives. Thirty-two representatives are chosen at random from the sales force and randomly assigned to the four call plans (eight per plan). The representatives follow their plans for 6 months, and their sales for the 6-month study period are recorded. These data are listed in the file P19_01.xlsx.

a. Do the sample data support the hypothesis that at least one of the call plans helps produce a higher average level of sales? Perform an appropriate statistical test and report a p-value.

b. If the sample data indicate the existence of mean sales differences across the call plans, which plans produce significantly different average sales levels at the 95% level?