Thanks Linda! One more question if you don't mind. When running my ZIP model MPlus obviously creates the binary variable (mine is alc#1). I assumed, but wanted to confirm, that this alc#1 variable takes the 0s from my original count variable (alc) and gives them 0s in alc#1 and anyone that has a non-zero value on alc gets a 1 for alc#1.
"In the binary part Mplus does logistic regression for Prob(u#=1), where u# is a binary latent inflation variable and u#=1 indicates that the individual is unable to assume any value except 0. This is called the zero class. "
So anyone who has a non-zero value on alc gets a 0 for alc#1. In other words, alc# (alc#=1) represents the inflation - the 0 part.
Stella Resko posted on Wednesday, November 19, 2008 - 4:16 pm
I was wondering if anyone has a good example (i.e., sample MPlus code) of a zero-inflated poisson model that includes an interaction? Thanks!
Q2. Typically ZIP modeling is applied to DVs. After all, how would you formulate influence from a ZIP variable (that is, having the ZIP variable as an IV)? Treating the counts as a continuous variable would be unsatisfactory, I would think.