Table 3.

Conditional probabilities of substance use (n=418, 702)

Class Prevalence	Frequent Polysubstance Users	Moderate Polysubstance Users	Polysubstance Experimenters	Non-Users
	6.9%	9.2%	22.8%	61.1%
Tobacco
Never Used	0.107	0.233	0.458	0.948
No Recent Use	0.247	0.448	0.518	0.047
1 or 2 Days Recent Use	0.164	0.260	0.017	0.004
3 to 9 Days Recent Use	0.179	0.057	0.003	0.001
10 to 30 Days Recent Use	0.302	0.002	0.004	0.001
Alcohol
Never Used	0.028	0.024	0.165	0.844
No Recent Use	0.084	0.115	0.554	0.095
1 or 2 Days Recent Use	0.170	0.520	0.213	0.048
3 to 9 Days Recent Use	0.364	0.308	0.043	0.008
10 to 30 Days Recent Use	0.355	0.034	0.025	0.005
Marijuana
Never Used	0.080	0.310	0.591	0.992
No Recent Use	0.184	0.289	0.341	0.003
1 or 2 Days Recent Use	0.139	0.258	0.039	0.003
3 to 9 Days Recent Use	0.180	0.121	0.016	0.001
10 to 30 Days Recent Use	0.417	0.022	0.014	0.001