Table 3 Contingency table of the toy example
From: Identity by descent and association analysis of dichotomous traits based on large pedigrees
Group |  | Number of distinct individuals who form pairs IBD at B|B | Number of distinct individuals who form pairs IBD at B|− but not B|B | Other |
|---|---|---|---|---|
Case | Observed | 2 | 3 | 1 |
| Â | Expected | (6/13)(2 + 0) = 12/13 | (6/13)(3 + 2) = 30/13 | (6/13)(1 + 5) = 36/13 |
Control | Observed | 0 | 2 | 5 |
| Â | Expected | (7/13)(2 + 0) = 14/13 | (7/13)(3 + 2) = 35/13 | (7/13)(1 + 5) = 42/13 |