. Author manuscript; available in PMC: 2012 Sep 1.

Published in final edited form as: Am J Drug Alcohol Abuse. 2011 Sep;37(5):376–382. doi: 10.3109/00952990.2011.568080

Table 3.

Parameter estimates, robust standard errors (SE) and associated p-values for our best-fitting model: Hurdle Binomial (HB) model. ‘s’ denotes significant covariates.

	Parameter estimate	Robust SE	p-value
Hurdle Part

Intercept^s	−1.984	0.495	0.0002
Gender	−0.094	0.562	0.868
Age^s	−0.64	0.286	0.031
Time	0.011	0.039	0.785
Participation^s	1.84	0.386	< 0.0001

Binomial part

Intercept	0.151	0.417	0.718
Gender	−0.043	0.543	0.936
Age^s	−0.491	0.234	0.042
Time	−0.007	0.016	0.654
Participation^s	−0.746	0.168	<0.0001

σ₁^s	1.688	0.254	< 0.0001
σ₂^s	1.726	0.217	< 0.0001
ρ^s	−0.319	0.156	0.047