Nurcombe and Fitzhenry-Coor (1979) have argued that training in diagnostic techniques should lead a clinician to generate (and test) more hypotheses in coming to a decision about a case. Suppose we take 10 psychiatric residents who are just beginning their residency and ask them to watch a videotape of an interview and to record their thoughts on the case every few minutes. We then count the number of hypotheses each resident includes in his or her written remarks. The experiment is repeated at the end of the residency with a comparable videotape. The data follow:

Subject: 1 2 3 4 5 6 7 8 9 10 Before: 84224 8313 9 After: 7 9 3 6 3 10 6 7 8 7

a. Analyze the data using Wilcoxon’s matched-pairs signed-ranks test.

b. What can you conclude?