Table 3.

Estimates of the Interaction Parameters^a

% of Families With a Parent's Genotype Missing	Method	Interaction Being Estimated	Allele Frequency
			0.2		0.3		0.4		0.5
			RR	95% CIb	RR	95% CI	RR	95% CI	RR	95% CI
0	QPL	I1	1.21	1.20, 1.22	1.21	1.20, 1.22	1.22	1.21, 1.23	1.22	1.21, 1.23
		I2	1.53	1.52, 1.55	1.53	1.51, 1.54	1.53	1.51, 1.54	1.53	1.52, 1.55
	Case-control	I1	1.21	1.20, 1.22	1.21	1.20, 1.22	1.22	1.21, 1.22	1.21	1.20, 1.22
		I2	1.65	1.62, 1.70	1.55	1.54, 1.57	1.54	1.52, 1.55	1.52	1.51, 1.54
	Case-only	I1	1.20	1.19, 1.21	1.20	1.19, 1.21	1.21	1.20, 1.22	1.21	1.20, 1.23
		I2	1.51	1.49, 1.52	1.51	1.49, 1.52	1.51	1.49, 1.53	1.52	1.50, 1.54
25	QPL	I1	1.21	1.20, 1.22	1.21	1.20, 1.22	1.22	1.21, 1.23	1.22	1.21, 1.23
		I2	1.53	1.51, 1.55	1.53	1.52, 1.54	1.53	1.51, 1.54	1.54	1.52, 1.55

Abbreviations: CI, confidence interval; QPL, quantitative polytomous logistic; RR, relative risk.

^aThe interaction parameter values used for simulation were I₁ = 1.2 and I₂ = 1.5.

^bConfidence intervals were based on the empirical standard errors using 1,000 estimates from 1,000 simulations.