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 w ith those found by The Departm ent o f Energy

(Money, June 2009).

Region West Northeast Midwest South Average Annual Energy Bill

$1,491 $2,319 $1,768 $1,758 A portion o f the ANOVA calculations are below:

Source o f Variation SS d f MS F p-value Between Groups 7531769 3 ? ? 7.13E-24 Within Groups 3492385 96 ?

Total 11024154 99

a. Complete the ANOVA table.

b. At the 1 % significance level, can w e conclude that average annual energy bills vary by region?

c. If sign ificant differences exist, use Tukey's m e th o d a t th e 1% significance level to determ ine which regions' means differ. P-69