11.14 Engineers are testing company fleet vehicle fuel economy (miles per gallon) ...

     11.14   Engineers are testing company fleet vehicle fuel economy (miles per gallon)   performance by using different types of fuel. One vehicle of each size is   tested. Does this sample prove that there is a significant difference in   treatment means? MPG2 87 Octane 89 Octane 91 Octane Ethanol 5% Ethanol 10%   Compact 27.2 30.0 30.3 26.8 25.8 Mid-Size 23.0 25.6 28.6 26.6 23.3 Full-Size   21.4 22.5 22.2 18.9 20.8 SUV 18.7 24.1 22.1 18.7 17.4