Table 3.
Results for illustration 3: Power calculations for sib-pair association with a tri-allelic locus with fixed genotypic values
| Frequencies alleles A, B, C | Effect size (%) | Actual N | Nr of groups represented | χ2(6) | Observed power | N required for power of 80% |
|---|---|---|---|---|---|---|
| .33/.33/.33 | 2.5 | 9,639 | 81 | 837.824 | 1 | 157 |
| .25/.5/.25 | 1.7 | 9,985 | 81 | 734.357 | 1 | 185 |
| .45/.45/.1 | .6 | 9,993 | 81 | 352.963 | 1 | 386 |
| .1/.45/.45 | 2.8 | 9,992 | 80 | 966.698 | 1 | 141 |
Note: Effect size is defined as % of variance explained by QTL; Actual N refers to actual number of sib-pairs in the analysis; Nr of groups represented refers to the number of groups, of the possible 81, that were represented in the analysis; χ2(6): the χ2-value of the test for association when the genotypic effects for all 6 distinguishable genotypes are fixed to zero; Observed power refers to the power observed for the modeled sample size N