. Author manuscript; available in PMC: 2014 Jun 30.

Published in final edited form as: Stat Med. 2012 Dec 12;32(14):2390–2405. doi: 10.1002/sim.5691

Table 7.

WGEE estimates of parameters, standard errors, and p-values from revised additive ZIP model based on Wald and score tests under MAR and MMDP for the CTN0018 Study.

Results from revised additive ZIP model for CTN0018 study
Parameter	Estimate	Standard errors	P-value for H₀ : β = 0
			Wald	Score
Log-linear part (μ_it)
β ₀	2.90	0.021	< 0.001	< 0.001
β₁ (intervention)	−0.09	0.025	< 0.001	< 0.001
β₂ (baseline USO)	0.012	0.0004	< 0.001	< 0.001
Logistic part (ρ_it)
β_u ₀	−0.68	0.144	< 0.001	< 0.001
β_u₁ (intervention)	0.371	0.200	0.065	0.068
β_u₂ (baseline USO)	−0.015	0.004	< 0.001	< 0.001