Table 1.

Descriptive statistics for joint trajectory variables.

	Analytic sample range		Boys		Girls		Test	Total
	Min	Max	M	SD	M	SD	t	M	SD
Bullying perpetration
Grade 7	0.00	2.20	0.23	0.31	0.23	0.35	0.02	0.23	0.33
Grade 8	0.00	2.40	0.30	0.40	0.27	0.39	0.87	0.28	0.39
Grade 9	0.00	3.20	0.22	0.41	0.21	0.33	0.55	0.21	0.36
Grade 10	0.00	2.40	0.17	0.27	0.18	0.33	−0.39	0.18	0.31
Grade 11	0.00	2.40	0.15	0.28	0.17	0.33	−0.56	0.16	0.30
Grade 12	0.00	3.40	0.16	0.34	0.15	0.27	0.41	0.15	0.30
Narcissistic personality traits
Grade 7	0.00	3.90	2.16	0.61	2.08	0.66	1.49	2.11	0.64
Grade 8	0.00	4.00	2.19	0.63	2.03	0.68	2.77**	2.10	0.66
Grade 9	0.00	3.90	2.21	0.62	1.98	0.71	3.85***	2.08	0.68
Grade 10	0.10	4.00	2.23	0.63	1.99	0.72	3.71***	2.09	0.69
Grade 11	0.00	3.90	2.20	0.60	2.02	0.70	2.87**	2.10	0.66
Grade 12	0.20	4.00	2.24	0.61	2.05	0.66	3.13**	2.13	0.65

Descriptive statistics are based on analytic sample N = 616; Sex coded as 0 = boys, and 1 = girls.

^**p < 0.01.

^***p < 0.001.