To determine the effect of fuel grade in fuel efficiency, 80 new cars of the same make with identical engines, were each driven for 1000 miles. Forty of the cars ran on regular fuel, and the other forty received premium grade fuel. The cars with the regular fuel averaged 27.2 miles/gal with a standard deviation of 1.2 miles/gal. The cars with the premium fuel averaged 28.1 miles/gal with a standard deviation of 2.0 miles/gal. Can you conclude that this type of car gets better mileage with premium grade fuel?