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Table 2 Contingency table

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

nBB 1

nB 1

n 1

 

Expected

pcase(nBB1 + nBB0)

pcase(nB1 + nB0)

pcase(n1 + n0 )

Control

Observed

nBB 0

nB 0

n 0

 

Expected

pcontrol(nBB1 +nBB0)

pcontrol(nB1 + nB0)

pcontrol(n1 + n0 )

  1. We tabulate affected individuals and unaffected individuals using a 2 × 3 contingency table. Using this table, we formulate our IBD test as a chi-square test. Under the alternative hypothesis, affected samples tend to form more pairs that are IBD at B|B or B|−. In other words, distinct affected individuals have a greater chance of forming pairs IBD at B|B or B|−. Throughout the table, nBB1/ nBB0 denotes the number of distinct affected/unaffected individuals who form pairs IBD at B|B; nB1/nB0 denotes the number of distinct affected/unaffected individuals who form pairs IBD at B|-, but not B|B; n1/n0 denotes the number of the rest of the affected/unaffected individuals.
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BMC Proceedings

ISSN: 1753-6561

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