Table 1.

T-tests for Gender Differences and Descriptive Statistics for Each Variable

Variable	t-test for gender differences	Full sample		Girls		Boys
	t (df)	M	SD	M	SD	M	SD
Problem behavior (Grade 8)	5.48 (1,276)	0.36	0.53	0.29	0.43	0.45	0.61
Problem behavior (Grade 6)	6.40 (1,276)	0.16	0.32	0.11	0.25	0.22	0.38
Academic achievement (Grade 6)	−4.96 (1,276)	3.14	0.64	3.22	0.60	3.05	0.67
School engagement (Grade 6)	−7.92 (1,276)	3.38	0.58	3.50	0.50	3.25	0.64
Peer rejection (Grade 6)	5.88 (1,276)	0.11	0.08	0.10	0.07	0.12	0.08
Peer acceptance (Grade 6)	−3.77 (1,276)	0.08	0.06	0.08	0.05	0.07	0.06
Friends’ problem behavior (Grade 6)	5.04 (1,276)	0.14	0.23	0.12	0.20	0.18	0.24
Friends’ academic achievement (Grade 6)	−4.48 (1,276)	3.22	0.46	3.27	0.44	3.16	0.48
Parental monitoring knowledge (Grade 6)	−5.08 (1,276)	3.52	0.65	3.61	0.59	3.42	0.70

All t-tests were significant at p<0.001. Gender is coded 0 for males and 1 for females