Question: In the comparison of two brands of gasoline, an investigator feels that the type of automobile in which the gasoline is used would make a difference in the mileage. Therefore it was decided to take 10 different makes of automobile and to draw a pair at random from within each make. One member of the pair of automobiles was assigned gasoline brand1 and the other member was gasoline brand 2. Then the mileages produced by the pairs of cars were as follows

Do the two brands appear to be significantly different, α = .05?Construct the95% confidence interval around the mean difference.