. Author manuscript; available in PMC: 2021 Aug 1.

Published in final edited form as: Sociol Methods Res. 2018 Jan 30;49(3):637–671. doi: 10.1177/0049124117747302

Table 2.

Maximum Likelihood Estimates of Means and Standard Deviations (SD) of (Zero-inflated) Poisson Parameters.

	Drinking in Last 30 Days			Drinking in Last 12 Months			Lifetime Drinking			Binge Drinking in Last Two Weeks
	λ (Poisson)	P (ZIP)	λ (ZIP)	λ (Poisson)	P (ZIP)	λ (ZIP)	λ (Poisson)	P (ZIP)	λ (ZIP)	λ (Poisson)	P (ZIP)	λ (ZIP)
Mean	2.723	.477	6.062	8.750	.698	13.026	15.425	.756	21.127	0.774	.307	2.662
SD	0.461	.039	0.561	1.209	.039	1.089	1.834	.040	1.348	0.129	.029	0.226

Note: ZIP = zero-inflated Poisson.