(6) The driver of a diesel-powered automobile decided to test the quality of three types of diesel fuel based on mpg. He obtained the data below. BRAND A 38.7 39.2 40.1 38.9 TOTAL 156.9 BRAND B 41.9 42.3 41.3 125.5 BRAND C 40.8 41.2 39.5 38.9 40.3 200.7 483.1 ΣΣΥ = 19465.77 (a) Does it make a difference for this driver, which brand to use? (b) Using Scheffe's method construct confidence intervals for the mean mileage of the three brands using an overall level of 0.95 (c) Which brand should he use? WHY?