The Department of Energy and the U.S. Environmental Protection Agency's 2012 Fuel Economy Guide provides fuel efficiency data for 2012 model year cars and trucks (Department of Energy website, April 16, 2012). The file named CarMileage provides a portion of the data for 316 cars. The column labeled Size identifies the size of the car (Compact, Midsize, and Large) and the column labeled Hwy MPG shows the fuel efficiency rating for highway driving in terms of miles per gallon. Use α = .05 and test for any significant difference in the mean fuel efficiency rating for highway driving among the three sizes of cars.