An automobile manufacturer wishes to test that claim that synthetic motor oil can improve gas mileage (in miles per gallon, or mpg). The table below shows the gas mileages, in mpg, of six cars that used synthetic motor oil. The table also shows the gas mileages in mpg of six cars that were using conventional motor oil (the controls). Synthetic 24 28 27 28 26 26 Control 26 25 25 27 27 27 Can you conclude that the mean gas mileage for cars using synthetic motor oil is more than the mean for the controls? Use the 0.05 level of significance. Compute the test statistic. a. Yes, 6.028
b. Yes, 8.572
c. No, 0.451
d. No. 0.331