TABLE 1.

Dependent Variables Used in Analysis (Sample sizes are in parentheses)

	Percentage with Stated Characteristic
Variable	Females	Males
Respondent's friend(s) use substancesa	(9,601)	(9,165)
	31%	32%
Respondent smokesa	(9,601)	(9,165)
	22%	21%
Respondent drinksa	(9,601)	(9,165)
	11%***	17%
Respondent engages in delinquent activitya	(9,601)	(9,165)
	25%***	39%
Respondent ever had sex	(9,495)	(9,056)
	37%**	39%
Respondent had sex before 15th birthdayb	(6,940)	(6,901)
	17%**	20%
Respondent used contraception at first sexc	(3,956)	(3,700)
	64%	65%

^aUsed as an independent variable in models predicting sexual activity among adolescents.

^bSample restricted to respondents at least 15 years old.

^cSample restricted to respondents who reported prior sexual activity.

Note: One-tailed t-tests were conducted to identify significant sex-related differences in risky adolescent behavior (including peer associations), previous sexual experience, and the use of contraception at first intercourse. The significance of these differences is shown in the Females column.

^***p ≥ .001;

^**p ≥ .01;

^*p ≥ .05.