Recall that in Exercise 10.31 (page 416) we compared 30-year and 15-year fixed rate mortgage loans for a number of Willamette Valley lending institutions. The results obtained are shown in Table 18.4. Use the Wilcoxon signed ranks test and the following MINITAB output to determine whether, for Willamette Valley lending institutions, the distribution of 30-year rates is shifted to the right or left of the distribution of 15-year rates. Use α = .01. As discussed in Example 18.4, MINITAB gives T+ as the Wilcoxon statistic. Find T- by subtracting T+ from n(n + 1 )/2, where n = 9.

Test of median = 0.0 versus median not = 0.0 N for N Test Wilcoxon Statistic Estimated Median 0.2355 45.0 0.009