Two fuel additives are being tested to determine their effect on gasoline mileage. Seven cars were tested with additive 1 and nine cars were tested with additive 2. The following data show the miles per gallon obtained with the two additives. Use α = .05 and the MWW test to see whether there is a significant difference between gasoline mileage for the two additives.
Additive 1 Additive 2
17.3 ............18.7
18.4 ............17.8
19.1 ............21.3
16.7 ............21.0
18.2 ............22.1
18.6 ............18.7
17.5 ............19.8
20.7
20.2