Independent Random Samples of Households in the Four U

Essay

Independent random samples of households in the four U.S.regions (Northeast,Midwest,South,and West)yielded data on last year's energy consumption.We are interested in assessing,at the 1% significance level,if the data provide sufficient evidence to conclude that last year's average energy consumption was different among the four U.S.regions.Assume that energy consumption in the four regions is Normally distributed.
SPSS was used to create the side-by-side boxplots shown below. What is the null hypothesis for assessing if the mean energy consumption was the same for the four regions?