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Does anyone have a good example (i.e., sample MPlus code) of a zeroinflated poisson model using the TWOLEVEL RANDOM command? Thanks! 


You can start with Example 9.2 and add: COUNT = y (i); and change the MODEL command as follows: MODEL: %WITHIN% s  y ON x; y#1 ON x; %BETWEEN% y s ON w xm; y WITH s; 


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 nonzero value on alc gets a 1 for alc#1. 


I am quoting from my ZIP post yesterday: "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 nonzero 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 zeroinflated poisson model that includes an interaction? Thanks! 


Do you mean interaction between 2 IVs? If so, you just use Define to create that interaction and use it as another IV. 

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