Table 2.

Type I error rate of the family-based association tests

model	origa	σb = 10		σ = 15
		probc	classd	prob	class
p = 0.05
additive	0.049	0.045	0.041	0.044	0.050
dom	0.049	0.042	0.051	0.042	0.048
rec	0.039	0.039	0.040	0.038	0.042
p = 0.01
additive	0.009	0.007	0.007	0.004	0.005
dom	0.010	0.004	0.004	0.008	0.009
rec	0.008	0.004	0.004	0.004	0.005

^aoriginal phenotype where all symptomatic subjects are affected.

^bwithin-class standard deviation

^cposterior probability of class membership used as a quantitative trait in affected subjects

^dmost probable class used as phenotype