Table 4.

Power (%) of NF and STDT Tests of Size α=.001 to Detect Association between Disease and a Diallelic Polymorphism, with the Use of Genotypes for 100 Sib Pairs

				Power for (%)
	True Modela			100 Discordant Sib Pairs			80 Discordant Sib Pairs and 20 Affected Sib Pairs
Frequency of B1	β	c1	Test Statistic	c1=1	c1=1/2	c1=0	c1=1	c1=1/2	c1=0
.2	.25	1	NF, Ψ=1	81	63	1	78	60	20
			NF, Ψ=K/(1-K)b	87	69	1	84	60	17
			STDT	81	68	0	61	40	0
.2	.5	1/2	NF, Ψ=1	84	90	22	81	85	20
			NF, Ψ=K/(1-K)	90	92	22	82	83	17
			STDT	82	87	5	61	71	0
.4	.3	0	NF, Ψ=1	2	70	93	1	70	91
			NF, Ψ=K/(1-K)	1	75	95	1	71	93
			STDT	0	53	81	0	29	62
.1	.3	1	NF, Ψ=1	72	66	1	81	71	1
			NF, Ψ=K/(1-K)	77	69	2	83	67	1
			STDT	72	65	0	69	60	0
.1	.3	1/2	NF, Ψ=1	83	86	9	86	88	13
			NF, Ψ=K/(1-K)	84	83	9	86	86	11
			STDT	81	81	0	68	70	0
.3	.3	0	NF, Ψ=1	1	39	79	0	47	85
			NF, Ψ=K/(1-K)	1	45	83	1	49	84
			STDT	1	20	58	0	15	44
.05	.35	1	NF, Ψ=1	72	67	0	78	68	1
			NF, Ψ=K/(1-K)	66	61	1	71	60	2
			STDT	63	61	0	38	32	0
.05	.8	1/2	NF, Ψ=1	86	88	5	77	78	7
			NF, Ψ=K/(1-K)	80	79	7	69	68	5
			STDT	77	76	0	44	50	0
.2	.4	0	NF, Ψ=1	0	26	61	0	34	81
			NF, Ψ=K/(1-K)	0	18	67	0	34	83
			STDT	0	4	24	0	11	31

^aP(y=1∣g=i)=0.1+c_iβ, where y is an indicator for disease, g = number of B₁ alleles in genotype, and c₀=0, c₁=1.

^bK is the population prevalence of the disease.