Mplus Users Guide v6.. - Muthén & Muthén

Examples: Mixture Modeling With Cross-Sectional DataEXAMPLE 7.29: TWO-GROUP IRT TWIN MODEL FORFACTORS WITH CATEGORICAL FACTOR INDICATORSUSING PARAMETER CONSTRAINTSTITLE: this is an example of a two-group IRT twinmodel for factors with categorical factorindicators using parameter constraintsDATA: FILE = ex7.29.dat;VARIABLE: NAMES = u11-u14 u21-u24 dz;CATEGORICAL = u11-u24;CLASSES = cdz (2);KNOWNCLASS = cdz (dz = 0 dz = 1);ANALYSIS: TYPE = MIXTURE;ALGORITHM = INTEGRATION;MODEL:%OVERALL%f1 BY u11u12-u14 (lam2-lam4);f2 BY u21u22-u24 (lam2-lam4);[f1-f2@0];f1-f2 (var);[u11$1-u14$1] (t1-t4);[u21$1-u24$1] (t1-t4);%cdz#1%f1 WITH f2(covmz);%cdz#2%f1 WITH f2(covdz);MODEL CONSTRAINT:NEW(a c e h);var = a**2 + c**2 + e**2;covmz = a**2 + c**2;covdz = 0.5*a**2 + c**2;h = a**2/(a**2 + c**2 + e**2);191