Mplus Users Guide v6.. - Muthén & Muthén

CHAPTER 17refers to the means of variables y1, y2, and y3 if they are independentvariables and refers to the intercepts if they are continuous dependentvariables. This statement indicates that the means or intercepts are freeparameters to be estimated using the default starting values.If the variables are categorical, the thresholds are referred to as follows,[y1$1 y1$2 y1$3 y2$1 y2$2];where y1 is a four category variable with three thresholds and y2 is athree category variable with two thresholds. y1$1 refers to the first andlowest threshold of variable y1; y1$2 refers to the next threshold; andy1$3 refers to the highest threshold. This statement means that thethresholds are free parameters to be estimated using the default startingvalues.For models with a mean structure, all means, intercepts, and thresholdsof observed variables are free to be estimated at the default startingvalues. The means and intercepts of continuous latent variables arefixed at zero in a single group analysis. In a multiple group analysis, themeans and intercepts of the continuous latent variables are fixed at zeroin the first group and are free to be estimated in the other groups. In amixture model, the means and intercepts of the continuous latentvariables are fixed at zero in the last class and are free to be estimated inthe other classes. The means and intercepts of categorical latentvariables are fixed at zero in the last class and are free to be estimated inthe other classes.CONVENIENCE FEATURES FOR THE MODELCOMMANDThere are several features that make it easier for users to specify themodel to be estimated. One feature is the list function. A user can use ahyphen to specify a list of variables, a list of equality constraints, and alist of parameter labels.When using the list function, it is important to know the order ofobserved and latent variables that the program expects. The order ofobserved variables is determined by the order of variables in theNAMES or USEVARIABLES options of the VARIABLE command. If586