Means and standard deviations for all substantive variables are presented in Table 1. The increase in teens' level of soft substance use from age 15 to age 16 was highly significant (t= 3.79, p < .001). For descriptive purposes, Table 1 also presents the results of simple univariate (or point-biserial where relevant) correlations among the key variables of interest in the study. These reveal a significant overall relation between teen substance use at both ages and peer reports of their own substance use at age 15. Adolescent gender and family income were also related to several variables in the study and hence were included as covariates in all analyses below.
