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. Author manuscript; available in PMC: 2018 Jul 1.
Published in final edited form as: Genet Epidemiol. 2017 May 2;41(5):427–436. doi: 10.1002/gepi.22046

Table 3.

The correlation between Y1, Y2 and Z1, Z2 under each setting

n = 500 n1 = 500, n2
= 500		 n1 = 400, n2
= 500		 n1 = 500, n2
= 400		 n1 = 400, n2
= 400
cor(Y1, Y2) 0.77
cor(Z1, Z2) 0.77 0.71 0.69 0.59

Since the estimated correlation between Y1 and Y2 was under-biased, b2^ became underestimated. Meanwhile, b1^ was inflated. Nevertheless, the estimates from our conditional analysis were still better than those from marginal analysis (i.e. closer to the true parameters in the conditional model).