Question 4 Researchers studied four different blends of gasolineto determine their effect on miles per gallon (MPG) of a car. Anexperiment was conducted with a total of 28 cars of the same type,model, and engine size, with 7 cars randomly assigned to eachtreatment group. The gasoline blends are referred to as A,B,C, andD.The MPGs are shown below in the table Gasoline Miles Per BlendGallon A 26 28 29 23 24 25 26 B 27 29 31 32 25 24 28 C 29 31 32 3424 28 27 D 30 31 37 38 36 35 29 We want to test the null hypothesisthat the four treatment groups have the same mean MPG vs. thealternative hypothesis that not all of the means are equal. a)Before carrying out the analysis, check the validity of anyassumptions necessary for the analysis you will be doing. Write abrief statement of your findings b) Test the null hypothesis thatthe four gasoline blends have the same mean MPGs, i.e., Test Ho:ua=ub=uc=ud vs. the alternative hypothesis Ha: not all the meansare equal. c) If your hypothesis test in (b) indicates asignificant difference among the treatment groups, conduct pairwisemultiple comparison tests on the treatment group means. Underlinegroups of homogeneous means. d) Briefly state your conclusions. (Use IBM SPSS for all calculations)