Do energy bills vary dramatically depending on where you live in the United States? Suppose 25 households from four regions in the United States are sampled. The values for the average annual energy bill are shown below and are consistent with those found by The Department of Energy (Money, June 2009).
a. Complete the ANOVA table.
b. At the 1 % significance level, can we conclude that average annual energy bills vary by region?
c. If significant differences exist, use Tukey's method at the 1% significance level to determine which regions' means differ.