Property Values II In Exercise 15.17, you used the sign test to determine whether th...

Property Values II In Exercise 15.17, you used the sign test to determine whether the data provided sufficient evidence to indicate a difference in the distributions of property assessments for assessors A and B.

a. Use the Wilcoxon signed-rank test for a paired experiment to test the null hypothesis that there is no difference in the distributions of property assessments between assessors A and B. Test by using a value of a near .05.

b. Compare the conclusion of the test in part a with the conclusions derived from the t-test in Exercise 10.46 and the sign test in Exercise 15.17. Explain why these test conclusions are (or are not) consistent.

Reference: Exercise 15.17

Property Values In Exercise 10.46, you compared the property evaluations of two tax assessors, A and B. Their assessments for eight properties are shown in the table:

a. Use the sign test to determine whether the data present sufficient evidence to indicate that one of the assessors tends to be consistently more conservative than the other; that is, . Test by using a value of a near .05. Find the p-value for the test and interpret its value.

b. Exercise 10.46 uses the t statistic to test the null hypothesis that there is no difference in the mean property assessments between assessors A and B. Check the answer for Exercise 10.46 and compare it with your answer to part a. Do the test results agree? Explain why the answers are (or are not) consistent.

Reference: Exercise 10.46

Tax Assessors In response to a complaint that a particular tax assessor (A) was biased, an experiment was conducted to compare the assessor named in the complaint with another tax assessor (B) from the same office. Eight properties were selected, and each was assessed by both assessors. The assessments (in thousands of dollars) are shown in the table.

Use the MINITAB printout to answer the questions that follow.

a. Do the data provide sufficient evidence to indicate that assessor A tends to give higher assessments than assessor B?

b. Estimate the difference in mean assessments for the two assessors.

c. What assumptions must you make in order for the inferences in parts a and b to be valid?

d. Suppose that assessor A had been compared with a more stable standard—say, the average would be calculated. If the test in part a is valid, can you use the paired-difference t-test to test the hypothesis that the bias, the mean difference between A’s assessments and the mean of the assessments of the four assessors, is equal to 0? Explain.