4. An experiment is carried out to compare five brands of gasoline. The following data give five observations on octane numbers of each of five gasolines:

Gasoline brands 1 2 3 4 5 77 71 73 75 77 72 73 67 72 73 Octane 79 73 71 72 72 79 77 69 69 76 76 67 70 73 70

(a) Construct ANOVA table for these data.

(b) Use the Tukey method to perform pairwise multiple comparisons test for all five gasolines. Use α = 0.05