A research firm wants to compare the miles per gallon of unleaded regular, mid-grade, and super-premium gasoline. Because of differences in the performance of different automobiles, seven different automobiles were selected and treated as blocks. Therefore, each brand of gasoline was tested with each type of automobile. The results of the trials, in miles per gallon, are shown in the following table.

a. What are the null and alternate hypotheses?

b. What are the test statistics?

c. What are the p-values?

d. Using a .05 significance level, what is your decision regarding the null hypotheses?

e. Interpret the result.
 

Automobile Regular Mid-grade Super Premium 1 21 23 26 2 23 22 25 3 24 25 27 4 24 24 26 5 26 26 30 6 26 24 27 7 28 27 32