Market research organization selects various car models every year and assesses their fuel efficiency. This year, in the analysis of the two similar subcompact models from two different manufacturers, the average mileage of 12 A-brand cars was 27.2 miles per gallon, and the standard deviation was 3.8 mpg. The 9 B-brand cars a tested were averaging 32.1 mpg with a standard deviation of 4.3 mpg. For a = 0.01, can it be concluded that mark A gives a lower average mileage than mark B? Find the value of p, interpret the result. What assumptions should you take to work on this problem?