. Author manuscript; available in PMC: 2011 Dec 1.

Published in final edited form as: J Child Psychol Psychiatry. 2010 Dec;51(12):1377–1385. doi: 10.1111/j.1469-7610.2010.02292.x

Table 1.

Means and standard deviations for the study variables by low- and middle-income background

Variable	Total		Middle-income		Low-income		Middle vs. Low

	Mean	SD	Mean	SD	Mean	SD
Gender	.51	.50	.54	.50	.48	.50	χ² = 2.27 (1 df)
Early delinquent involvement	.21	.30	.18	.28	.25	.32	t = −3.22^* (746 df)
Early-onset sex	.09	.29	.06	.24	.12	.32	χ² = 8.03^* (1 df)
Early alcohol use	.24	.43	.30	.46	.20	.40	χ² = 9.71^* (1 df)
Delinquency age 14	.20	.35	.20	.33	.21	.36	t = .45 (776 df)
Delinquency age 15	.20	.34	.17	.30	.22	.37	t = −2.08^* (781 df)
Delinquency age 16	.19	.35	.17	.32	.22	.36	t = 2.18^* (768 df)
Delinquency age 18	.17	.30	.17	.32	.17	.28	t = .25 (755 df)
Alcohol age 14	.36	.69	.33	.66	.38	.72	t = −1.01 (776 df)
Alcohol age 15	.43	.75	.40	.73	.47	.77	t = −1.30 (781 df)
Alcohol age 16	.51	.79	.50	.77	.51	.80	t = −.32 (768 df)
Alcohol age 18	.75	.90	.80	.91	.71	.90	t = 1.38 (755 df)
Crime	1.72	5.28	1.58	5.51	1.84	5.05	t = −.67 (784 df)
Risky sex	.23	.42	.25	.43	.23	.42	χ² = .26 (1 df)
AUDs	.37	.48	.37	.48	.37	.48	χ² = .04 (1 df)

Note.

p < .05.