Conducts statistical tests comparing latent classes on a specific variable.
Examples
if (FALSE) { # \dontrun{
fit <- gmm_survey(data = mcs_simulated, id = "id", time = "age",
outcome = "selfcontrol", n_classes = 3,
keep_data = TRUE)
compare_classes(fit, var = "baseline_risk", test = "wald")
} # }