Suppose that an automobile manufacturer designed a radically

Suppose that an automobile manufacturer designed a radically new lightweight engine and wants to recommend the grade of gasoline that will have the best fuel economy. The four grades are: regular, below regular, premium, and super premium. The test car made three trial runs on the test track using each of the four grades and the miles per gallon recorded. At the 0.05 level, whatis the critical value of F used to test the hypothesis that the miles per gallon (shown below) for each fuel is the same?

Solution

Here, we use F test (ANOVA) to see if there is a significant difference between the groups.

df1 = number of groups - 1 = 4 - 1 = 3
df2 = number of runs - number of groups = (3 + 3 + 3 + 3) - 4 = 8

Thus, using table/technology, at 0.05 level,

Fcrit = 4.066180551 = 4.07 [OPTION B, ANSWER]