. Author manuscript; available in PMC: 2018 Jan 1.

Published in final edited form as: Genet Epidemiol. 2016 Nov 18;41(1):4–17. doi: 10.1002/gepi.22025

Table 2. Models of learning performance for LP status and NS-LP score.

Model A: Y_i = a₀ + a_zZ_i. Model B: Y_i = b₀ + b_LL_i. Model C: Y_i = c₀ + c_LL_i + c_zZ_i. Learning performance score Y_i is average of working memory, episodic memory, vocabulary, and reading exams. Each exam score was scaled to zero mean and unit variance after controlling for age, sex, household income, parents’ education, and first two PCs of genotype. Indicator L_i=1 for positive LP diagnosis and L_i=0 otherwise. NS-LP score $Z_{i} : = Z_{i}^{v}$ for v = 0.01. (a) F-test for respective models; degrees of freedom (df) are 1 and 477 for Models A and B, and df are 2 and 476 for Model C. (b) F-test for respective coefficients with 1 and 477 df’s. (c) Model C’s fit is 44% better than Model B as determined by percentage increase in adjusted R².

	Summary of model fits
	Adjusted R²	R²	p-value ^a
Model A	0.024	0.026	3.7E-04
Model B ^c	0.036	0.038	1.6E-05
Model C ^c	0.052	0.056	9.7E-07

	Model estimates
	beta	T	p-value ^b
Model A
a₀	0.57	3.50	5.1E-04
a_Z	−0.36	−3.56	4.1E-04
Model B
b₀	0.04	1.21	0.23
b_L	−0.49	−4.37	2.0E-05
Model C
c₀	0.51	3.18	1.5E-03
c_L	−0.44	−3.85	1.3E-04
c_Z	−0.31	−3.01	2.8E-03