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. Author manuscript; available in PMC: 2014 Dec 1.
Published in final edited form as: Drug Alcohol Depend. 2013 Aug 11;133(2):10.1016/j.drugalcdep.2013.07.034. doi: 10.1016/j.drugalcdep.2013.07.034

Table 3.

Goodness-of-fit statistics for bivariate models of early-onset cannabis use and early school leaving.

Model versus Δχ2 Δdf P-value
1 General ACE model
2 Drop phenotypic correlation 1 51.27 3 <0.001
3 Drop genetic correlation (rg) 1 1.04 1 0.31
4 Drop shared environmental correlation (rc) 1 1.79 1 0.18
5 Drop residual correlation (re) 1 0.28 1 0.60
6 Drop genetic and shared environmental correlations (rg and rc) 1 36.02 2 <0.001
7 Drop A influences on early-onset cannabis use 2 20.51 1 <0.001
8 Drop C influences on early-onset cannabis use 2 2.43 1 0.12
9 Drop A influences on school leaving 2 2.92 1 0.09
10 Drop C influences on school leaving 2 6.69 1 <0.01

A=additive genetic influences, C=shared environmental influences, E=residual influences