[R] latent class model in R

[Junjun Xie]

Hi  Everyone,
I am facing the problem of running the latent class model in R. By "mmlcr", the program always shows as following,

Error in model.frame(formula, rownames, variables, varnames, extras, extranames,  :      invalid variable type

Does anyone happen to know why this happened? I am stopped at this step.  Thank you very much for the answer.


Best regards, 

Junjun Xie