. Author manuscript; available in PMC: 2010 Jan 27.

Published in final edited form as: Int J Sci Educ. 2008 Jun;30(8):1003. doi: 10.1080/09500690701324190

Table 4.

Fit Indices and Parameter Estimates from the Full-Sex Limitation Model and Sub-models Fit to Science Composite Score

Model	Δχ²	Δdf	AIC	Δχ²	Δdf	p	Male			Female			r_G	r_C	s²_m	s²_f
							a²_m	c²_m	e²_m	a²_f	c²_f	e²_f

Full (rG free)	7.255	7	−6.745	-	-	-	0.62 (.47–.73)	0.14 (.04–.28)	0.24 (.21–.28)	0.62 (.49–.74)	0.15 (.05–.28)	0.23 (.20–.26)	0.50	1.00	1.06	0.95
Full (rC free)	7.255	7	−6.745	-	-	-	0.62 (.47–.73)	0.14 (.04–.28)	0.24 (.21–.28)	0.62 (.49–.74)	0.15 (.05–.28)	0.23 (.20–.26)	0.50	1.00	1.06	0.95
Common effects	7.255	8	−8.745	0.000	1	0.988	0.62 (.48–.73)	0.14 (.04–.28)	0.24 (.21–.28)	0.62 (.49–.74)	0.15 (.05–.28)	0.23 (.20–.26)	0.50	1.00	1.06	0.95
							a²		c²		e²

Scalar	7.567	10	−12.433	0.312	3	0.958	0.62 (.54–.71)		0.14 (.07–.22)		0.23 (.21–.25)		0.50	1.00	1.06	0.95
Null model	42.209	11	20.209	34.953	4	0.000	0.63 (.55–.71)		0.14 (.06–.21)		0.23 (.21–.25)		0.50	1.00	1.00	1.00

Note. Δχ² = change in chi-squared firstly in comparison to the fully saturated model and then in comparison to the full sex-limitation model; Δdf = change in degrees of freedom between comparison models; p = significance level comparing reduced models to the full model; a²_m, c²_m, e²_m = additive genetic, shared environmental and non-shared environmental estimates for males; a²_f, c²_f, e²_f = additive genetic, shared environmental and non-shared environmental estimates for females; r_G = genetic correlation for opposite-sex DZ twins; r_C = shared environmental correlation for opposite-sex twins; s²_m = predicted variance in males, s²_f = predicted variance in females. See text for a description of the model.