A grassroots group opposed to a proposed increase in the gas tax claimed that the increase would hurt working-class people the most, since they commute the farthest to work. Suppose that the group randomly surveyed 24 individuals and asked them their daily one-way commuting mileage. The results are in the table below. Using a 5% significance level, test the hypothesis that the three mean commuting mileages are the same.
Working-class | Professional (middle incomes) | Professional (Wealthy)
17.8 | 16.5 | 8.5
26.7 | 17.4 | 6.3
49.4 | 22.0 | 4.6
9.4 | 7.4 | 12.6
65.4 | 9.4 | 11.0
47.1 | 2.1 | 28.6
19.5 | 6.4 | 15.4
51.2 | 13.9 | 9.3