Martin Motors has in stock three cars of the same make and model. The president would like to compare the gas consumption of the three cars using four different types of gas. For each trial, a gallon of gas was added to an empty tank, and the car was driven until it ran out of gas. The following shows the # of miles driven in each trial.
Distance (miles)
Types of Gasoline Car A Car B Car C
Regular ; 22.4 20.8 21.5
Super regular 17.0 19.4 20.7
Unleaded 19.2 20.2 21.2
Premium unleaded 20.3 18.6 20.4
Using the .05 level of significance: a. Is there a difference among the types of gas? b. Is there a difference in the cars?
