13-21. The marketing department of ACE Industries is investigating the sales appeal of two different display formats for a given product—one with and one without animation. The two displays are installed at each of 12 stores for one week and the numbers of items purchased from each display are:

Animated Non animated Animated Non animated Store Display Display Store Display Display 1 27 25 7 33 27 2 35 30 8 37 29 3 17 10 9 21 19 4 20 21 10 24 17 5 22 20 11 19 22 6 39 30 12 44 30 Is the animated display more effective than the nonanimated one? Employ the Wilcoxon signed-rank test with α = 0.05.

13-22. Resolve Exercise 19 using the large-sample Wilcoxon signed rank test.