In growht mixture models: can you use the t statistic to evaluate the significance of the variance of the latent slope ? I have encountered this in a couple of articles. Should one not use a mixture of chisquare distributions to test for this ?
I was wondering. Suppose I have a GMM, with two classes. For both classes I specify a random intercept and slope. To test the significance of the variance of the slope growth factor I fit a model including a random slope and a model with a fixed slope. I compare the log likelihood values of these two models. Is this allowed ? Are this still nested models; what if the partitioning of the patients in two classes is different in these two models ?