5.A company that employs a large number of salespeople is interested in learning which of the salespeople sell the most: those strictly on commission, those with a fixed salary, or those with a reduced fixed salary plus a commission. The previous month’s records for a sample of salespeople are inspected and the amount of sales (in dollars) is recorded for each，as shown in the table.(30 %)

Test to determine if a difference exists in the mean sale amounts among the three compensation systems. Test using a = 0.025.