Table 2.

Power of association analyses at Locus D^a

	Power, no covariates		Power, adjustedb
	α = 0.05	α = 0.01	α = 0.05	α = 0.01	Mean d.f.c
6 Markers d
Haplotypes	0.240	0.088	0.059	0.009	9.04
Clusters, ε = 0.4e	0.272	0.104	--	--	4.48
Clusters, ε = 0.5	0.271	0.098	0.079	0.022	4.43
8 Markers f
Haplotypes	0.448	0.206	0.112	0.025	14.37
Clusters, ε = 0.7e	0.470	0.239	--	--	10.26
Clusters, ε = 0.5	0.448	0.236	0.135	0.019	10.26

^aPower was measured over 800 data sets of 500 each cases and controls.

^bSex and number of DRB1*04 alleles were included as covariates.

^cSee Table 1. Values shown are from analyses without covariates; mean d.f. from adjusted analyses were nearly identical.

^dSNPs 3914–3919.

^eValue of ε maximizing power for score test without covariates.

^fSNPs 3913–3920.