3. A study was conducted to compare automobile gasoline mileage for three formulations of gasoline. Four automobiles, all of the same make and model, were used, and each formulation was tested in each automobile, thus eliminating automobile-to-automobile variability. The data (in miles per gallon) follow. Data Automobile Formulation 1 3 4 A 25.7 27.0 27.3 26.1 27.2 28.1 27.9 27.7 26.1 27.5 26.8 27.8 a. Do the data provide sufficient evidence indicate a difference in mean mileage per gallon for the three gasoline formulations? b. Is there evidence of a difference in mean mileage for the four automobiles?

3. A study was conducted to compare automobile gasoline mileage for three formulations of gasoline. Four automobiles, all of the same make and model, were used, and each formulation was tested in each automobile, thus eliminating automobile-to-automobile variability. The data (in miles per gallon) follow. Data Automobile Formulation 1 3 4 A 25.7 27.0 27.3 26.1 27.2 28.1 27.9 27.7 26.1 27.5 26.8 27.8 a. Do the data provide sufficient evidence indicate a difference in mean mileage per gallon for the three gasoline formulations? b. Is there evidence of a difference in mean mileage for the four automobiles?