Wilcoxon matched pairs signed ranks test

4. Add up ranks of positive differences and ranks
   of negative differences. Call the sum of the
   smaller group T

• Sum of + ranks: 17 (n+ =4)


• Sum of – ranks: 38 (n– = 6)


• T (sum of ranks of smaller group) = 17

Patients 1 2 3 4 5 6 7 8 9 10

Drug score 19 11 14 17 23 11 15 19 11 8

Placebo score 22 18 17 19 22 12 14 11 19 7

difference - 3 - 7 - 3 - 2 1 - 1 1 8 - 8 1

Rank - 6.5 8 6.5 5 2.5 9.5

Rank + 2.5 2.5 9.5 2.5