Home foreclosures were up 47% in March 2008 compared to the previous year (realestate.msn.com; MSN Real Estate, April 2008). The data show home foreclosure rates (as % change from the previous year) for a sample of cities in two regions of the United States, the Northeast and the Southwest.

Northeast: 2.99, -2.36, 3.03, 1.01, 5.77, 9.95, -3.52, 7.16, -3.34, 4.75, 5.25, 6.21, 1.67, -2.45, -0.55, 3.45, 4.50, 1.87, -2.15, -0.75

Southwest: 10.15, 23.05, 18.95, 21.16, 17.45, 12.67, 13.75, 29.42, 11.45, 16.77, 12.67, 13.69, 25.81, 21.16, 19.67, 11.88, 13.67, 18.00, 12.88

a) Write the null and alternative hypotheses.

b) Check the conditions for a Wilcoxon rank sum (or Mann-Whitney) test.

c) Complete the test and report your conclusion.

d) Make histograms of each group. Discuss whether you would choose a nonparametric test for these data or a two sample t-test (as in Chapter 13).