9. (5 marks) In a test of the effectiveness of a device intended to increase gas mileage, four cars were operated with m without the device. The mileages (in mpg), as well as some sample statistics, are given in the table below. CAR WITHOUT DEVICE WITH DEVICE DIFFERENCE 22.5 _4 3 1.7 71 28.8 ,1 33.5 2 29.125 2 4.82 1.41 The researcher Wishes to show that the device actually increases the average mileage. Conduct an appropriate hypothesis test at a = 0.10. (HINT: Are the measurements dependent or independent?)