Variable	Unweighted sample	Weighted sample
Male	0.522	0.522
Black	0.243	0.144
Hispanic	0.237	0.143
Lived with biological parents at 12	0.522	0.573
House broken in by age 12	0.159	0.152
Witness of gun shooting by age 12	0.104	0.086
Victim of bullying by age 12	0.169	0.176
Highest grade completed by 19	11.780	11.895
	(0.030)	(0.030)
AFQT percentile score	41.738	47.264
	(0.681)	(0.717)
Mother’s highest grade completed	12.224	12.746
	(0.072)	(0.071)
Number of (full) siblings	2.124	2.006
	(0.032)	(0.032)
Age of younger sibling	16.042	15.985
	(0.024)	(0.024)
Age of older sibling	18.065	18.044
	(0.024)	(0.025)
Age gap	2.023	2.060
	(0.022)	(0.022)

Note: Standard errors of the sample means in parentheses. Statistics are based on the sample used for estimation of the dynamic smoking model including 1,650 pairs of siblings. Weighted statistics are computed using a set of cross-sectional weights for the survey round in which the respondent is 19 years old. Ages of the younger and older siblings refer to the age in the first year the behavior of younger siblings is observed.