The following Excel output summarizes the results for a one-way analysis of variance experiment in which the treatments were three different hybrid cars and the variable measured was the miles per gallon (mpg) obtained while driving the same route.

Hybrid 1: x1 = 38, n1 = 20

Hybrid 2: x2 = 48, n2 = 15

Hybrid 3: x3 = 39, n3 = 18

a. At the 5% significance level, can we conclude that average mpg differs between the hybrids?
b. If significant differences exist, use Tukey's HSD method at the 5% significance level to determine which hybrids' means differ.

Source of Variation SS df Between 1034.51 2517.26 19.86 4.49E-07 3.182 Groups Within 1302.41 50 26.05 Groups F p-value F crit Tota 2336.92 52