Intraclass correlations by zygosity, genetic model parameter estimates, and nested model statistics of each variable controlling for age and nonverbal reasoning.

Note. Number of twin pairs ranged from 210 to 227 for MZ and from 80 to 84 for DZ. All ACE models had a satisfactory goodness of fit indicated by a nonsignificant χ2change between the saturated and the ACE models (Δχ2 ranged from 0.81 to 6.77, Δdf = 6, ps>.05). MZ = Monozygotic twins; DZ = Dizygotic twins; a2 = additive genetic variance; c2 = shared environment variance; e2 = nonshared environment variance; Δχ2 and Δdf are the differences between the ACE and the nested models.(95% confidence intervals in parentheses).

注：同卵双生子（Monozygotic twins, MZ）的双生子对数量范围为210至227，异卵双生子（Dizygotic twins, DZ）的双生子对数量范围为80至84。所有ACE模型均具备良好的拟合优度，饱和模型与ACE模型间的χ²变化无统计学显著性（Δχ²范围为0.81至6.77，Δdf=6，ps>0.05）。其中MZ代表同卵双生子，DZ代表异卵双生子；a²代表加性遗传方差（additive genetic variance），c²代表共同环境方差（shared environment variance），e²代表非共同环境方差（nonshared environment variance）；Δχ²与Δdf为ACE模型与嵌套模型间的差值。95%置信区间标注于括号内。