15.29 Traffic Control Two methods for controlling traffic, A and B, were used at each of n = 12 intersections for a period of 1 week, and the numbers of accidents that occurred during this time period were recorded. The order of use (which method would be employed for the first week) was selected in a random manner. You want to know whether the data provide sufficient evidence to indicate a difference in the distributions of accident rates for traffic control methods A and B.

a. Analyze using a sign test.

b. Analyze using the Wilcoxon signed-rank test for a paired experiment.

Method Method Intersection A B Intersection A B 1 2 56 5 4 7 6 4 8 3 8 9 9 4 3 2 10 5 6 69 30 26185- 561 112 2 3 4 7 9