. Author manuscript; available in PMC: 2010 Mar 11.

Published in final edited form as: Eur J Pers. 2008 May 1;22(3):247–268. doi: 10.1002/per.671

Table 3.

Regression and mediation analyses for GPA regressed on sex and personality traits.

Step	Predictors	β	p	R	R²
Step 1	Sex	.23	< .001	.23	.053
Step 2a	Sex	.24	< .001	.36	.128
	Achievement	.22	< .001
	Sex × Achievement	.08	< .05
Step 2b	Sex	.19	< .001	.35	.121
	Control	.26	< .001
	Sex × Control	.02	ns
Step 2c	Sex	.12	< .001	.30	.090
	Aggression	-.25	< .001
	Sex × Aggression	-.02	ns
Step 3	Sex	.17	< .001	.42	.174
	Achievement	.16	< .001
	Control	.16	< .001
	Aggression	.14	< .001
	Sex × Achievement	.06	< .05

Note. For Sex, 0 = male, 1 = female. All significance levels were adjusted for the non-independence of the twin observations. ns = nonsignificant at p < .05.