Is the overall cost of living higher or lower for urban areas in particular geographical regions of the United States? Consider the random sample of 80 urban areas provided in the file P10_71.XLS. In particular, determine whether the mean composite (cost of living) value in urban areas of the northeastern states is higher than the mean composite value in urban areas of each of the following:

(a) Southeastern states, (b) central states, (c) southwestern states, and (d) northwestern states. Note that you will need to assign each of the urban areas in the given sample to one of these five geographical regions before you can proceed further.

a. Before conducting any hypothesis tests on the difference between various pairs of mean composite values, perform a test for equal population variances in each pair of geographical regions. For each pair, report a p-value and interpret its meaning.

b. Based on your conclusions in part a, which test statistic should be used in performing a test for a difference between population means in each pair?

c. Given your conclusions in part b, perform a test for the difference between composite cost of living values in each pair of geographical regions. For each pair, report a p-value and interpret its meaning.