Mplus Users Guide v6.. - Muthén & Muthén

Special Modeling Issuesgroup and last class and are free and unequal in the other groups orclasses except when a categorical latent variable is regressed on acontinuous latent variable. In this case, the means and intercepts ofcontinuous latent variables are fixed at zero in all classes.• Logit means and intercepts of categorical latent variables are fixed atzero in the last class and free and unequal in the other classes.Following are the default settings for variances/residual variances/scalefactors:• Variances of observed independent variables are estimated as orfixed at the sample values when they are included in the modelestimation.• In single group analysis and multiple group analysis, variances andresidual variances of continuous and censored observed dependentvariables and continuous latent variables are free. In multiple classanalysis, variances/residual variances of continuous and censoredobserved dependent variables and continuous latent variables arefree and equal across classes.• In single group analysis using the Delta parameterization, scalefactors of latent response variables for categorical observeddependent variables are fixed at one. In multiple group analysisusing the Delta parameterization, scale factors of latent responsevariables for categorical observed dependent variables are fixed atone in the first group and are free and unequal in the other groups.• In single group analysis using the Theta parameterization, variancesand residual variances of latent response variables for categoricalobserved dependent variables are fixed at one. In multiple groupanalysis using the Theta parameterization, variances and residualvariances of latent response variables for categorical observeddependent variables are fixed at one in the first group and are freeand unequal in the other groups.Following are the default settings for covariances/residual covariances:• Covariances among observed independent variables are estimated asor fixed at the sample values when they are included in the modelestimation.• In single group analysis and multiple group analysis, covariancesamong continuous latent independent variables are free except whenthey are random effect variables defined by using ON or XWITH in409