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 individuals and asked them their daily one-way commuting mileage. The results are as follows.
working-class
| professional (middle incomes)
| professional (wealthy)
|
17.8 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
19.5
| 15.4
| 15.4
|
51.2 | 13.9
| 9.3
|
Determine whether or not the variance in mileage driven is statistically the same among the working class and professional (middle income) groups. Use a 5% significance level.