Introduction
Cluster analysis techniques are not the only way to find non-observed groupings in your data. In fact, from several perspectives cluster analysis may not be the best way to determine these groupings. There are several latent variable approaches that are available. In this unit we will explore two of them: Latent variable mixture models and latent class analysis.
The advantages of these approaches over cluster analysis are that they are model based, generating probabilities for group membership. It is possible to test these models and to analyze their goodness of fit. The downside to this approach is that it requires specialized software that is more complex to run than general purpose statistical packages. We will demonstrate these techniques using the Mplus from Muthén & Muthén. We will also use Stata for descriptive, subsidiary analyses and for an example of finite mixture modeling.
Latent variable mixture models will use continuous predictors and the latent class analysis will use binary predictor variables. We will the reading, writing, math, science and social studies test scores from the hsb6a dataset. For the binary predictor variables we will be median splits on each of the tests to create hiread, hiwrite, himath, hisci and hiss.
Looking at the data
use http://www.philender.com/courses/data/hsb6a, clear describe Contains data from hsb6a.dta obs: 600 highschool and beyond (600 cases) vars: 23 24 Oct 2003 14:18 size: 31,200 (99.0% of memory free) ------------------------------------------------------------------------------- storage display value variable name type format label variable label ------------------------------------------------------------------------------- id int %9.0g gender byte %9.0g gl race byte %12.0g rl ses byte %9.0g sl sch byte %9.0g scl prog byte %9.0g pl locus float %9.0g locus of control concept float %9.0g self-concept mot float %9.0g motivation career byte %14.0g cl career choice read float %9.0g reading score write float %9.0g writing score math float %9.0g math score sci float %9.0g science score ss float %9.0g social studies score hiread byte %9.0g hiwrite byte %9.0g himath byte %9.0g hisci byte %9.0g hiss byte %9.0g sum read write math sci ss hiread hiwrite himath hisci hiss Variable | Obs Mean Std. Dev. Min Max -------------+-------------------------------------------------------- read | 600 51.90183 10.10298 28.3 76 write | 600 52.38483 9.726455 25.5 67.1 math | 600 51.849 9.414736 31.8 75.5 sci | 600 51.76333 9.706179 26 74.2 ss | 600 52.04567 9.879228 25.7 70.5 -------------+-------------------------------------------------------- hiread | 600 .525 .4997913 0 1 hiwrite | 600 .54 .4988133 0 1 himath | 600 .4966667 .5004061 0 1 hisci | 600 .5266667 .499705 0 1 hiss | 600 .6483333 .477889 0 1
A 2 Class Latent Variable Mixture Model Using Mplus
Data: File is D:\mplus\data\hsb6.dat ; Variable: Names are id gender race ses sch prog locus concept mot career read write math sci ss hiread hiwrite himath hisci hiss; Usevariables are read write math sci ss; classes = c(2); Analysis: Type=mixture; MODEL: %C#1% [read write math sci ss * 30 ]; %C#2% [read write math sci ss * 60 ]; SUMMARY OF ANALYSIS Number of groups 1 Number of observations 600 Number of dependent variables 5 Number of independent variables 0 Number of continuous latent variables 0 Number of categorical latent variables 1 Observed dependent variables Continuous READ WRITE MATH SCI SS Categorical latent variables C Estimator MLR Information matrix OBSERVED Optimization Specifications for the Quasi-Newton Algorithm for Continuous Outcomes Maximum number of iterations 1000 Convergence criterion 0.100D-05 Optimization Specifications for the EM Algorithm Maximum number of iterations 500 Convergence criteria Loglikelihood change 0.100D-06 Relative loglikelihood change 0.100D-06 Derivative 0.100D-05 Optimization Specifications for the M step of the EM Algorithm for Categorical Latent variables Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Optimization Specifications for the M step of the EM Algorithm for Censored, Binary or Ordered Categorical (Ordinal), Unordered Categorical (Nominal) and Count Outcomes Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Maximum value for logit thresholds 15 Minimum value for logit thresholds -15 Minimum expected cell size for chi-square 0.100D-01 Optimization algorithm EMA Random Starts Specifications Number of initial stage starts 10 Number of final stage starts 1 Number of initial stage iterations 10 Initial stage convergence criterion 0.100D+01 Random starts scale 0.500D+01 Random seed for generating random starts 0 Input data file(s) D:\mplus\data\hsb6.dat Input data format FREE Loglikelihood values at local maxima, seeds, and initial stage start numbers: -10490.737 285380 1 THE MODEL ESTIMATION TERMINATED NORMALLY TESTS OF MODEL FIT Loglikelihood H0 Value -10490.737 Information Criteria Number of Free Parameters 16 Akaike (AIC) 21013.474 Bayesian (BIC) 21083.825 Sample-Size Adjusted BIC 21033.029 (n* = (n + 2) / 24) Entropy 0.853 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASSES BASED ON THE ESTIMATED MODEL Latent Classes 1 274.08927 0.45682 2 325.91073 0.54318 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASS PATTERNS BASED ON ESTIMATED POSTERIOR PROBABILITIES Latent Classes 1 274.08958 0.45682 2 325.91042 0.54318 CLASSIFICATION OF INDIVIDUALS BASED ON THEIR MOST LIKELY LATENT CLASS MEMBERSHIP Class Counts and Proportions Latent Classes 1 272 0.45333 2 328 0.54667 Average Latent Class Probabilities for Most Likely Latent Class Membership (Row) by Latent Class (Column) 1 2 1 0.957 0.043 2 0.042 0.958 MODEL RESULTS Estimates S.E. Est./S.E. Latent Class 1 Means READ 43.783 0.642 68.152 WRITE 45.068 0.730 61.738 MATH 44.794 0.469 95.540 SCI 44.446 0.740 60.051 SS 45.574 0.658 69.237 Variances READ 46.463 2.785 16.681 WRITE 49.427 3.011 16.415 MATH 46.634 3.133 14.884 SCI 49.022 3.388 14.470 SS 62.215 4.109 15.141 Latent Class 2 Means READ 58.730 0.605 97.000 WRITE 58.538 0.497 117.764 MATH 57.782 0.687 84.120 SCI 57.917 0.499 116.079 SS 57.488 0.589 97.629 Variances READ 46.463 2.785 16.681 WRITE 49.427 3.011 16.415 MATH 46.634 3.133 14.884 SCI 49.022 3.388 14.470 SS 62.215 4.109 15.141 Categorical Latent Variables Means C#1 -0.173 0.133 -1.298 QUALITY OF NUMERICAL RESULTS Condition Number for the Information Matrix 0.383E-02 (ratio of smallest to largest eigenvalue)
A 3 Class Latent Variable Mixture Model Using Mplus
Data: File is D:\mplus\data\hsb6.dat ; Variable: Names are id gender race ses sch prog locus concept mot career read write math sci ss hiread hiwrite himath hisci hiss; Usevariables are read write math sci ss; classes = c(3); Analysis: Type=mixture; MODEL: %C#1% [read write math sci ss * 30 ]; %C#2% [read write math sci ss * 45 ]; %C#3% [read write math sci ss * 60 ]; SUMMARY OF ANALYSIS Number of groups 1 Number of observations 600 Number of dependent variables 5 Number of independent variables 0 Number of continuous latent variables 0 Number of categorical latent variables 1 Observed dependent variables Continuous READ WRITE MATH SCI SS Categorical latent variables C Estimator MLR Information matrix OBSERVED Optimization Specifications for the Quasi-Newton Algorithm for Continuous Outcomes Maximum number of iterations 1000 Convergence criterion 0.100D-05 Optimization Specifications for the EM Algorithm Maximum number of iterations 500 Convergence criteria Loglikelihood change 0.100D-06 Relative loglikelihood change 0.100D-06 Derivative 0.100D-05 Optimization Specifications for the M step of the EM Algorithm for Categorical Latent variables Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Optimization Specifications for the M step of the EM Algorithm for Censored, Binary or Ordered Categorical (Ordinal), Unordered Categorical (Nominal) and Count Outcomes Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Maximum value for logit thresholds 15 Minimum value for logit thresholds -15 Minimum expected cell size for chi-square 0.100D-01 Optimization algorithm EMA Random Starts Specifications Number of initial stage starts 10 Number of final stage starts 1 Number of initial stage iterations 10 Initial stage convergence criterion 0.100D+01 Random starts scale 0.500D+01 Random seed for generating random starts 0 Input data file(s) D:\mplus\data\hsb6.dat Input data format FREE THE MODEL ESTIMATION TERMINATED NORMALLY TESTS OF MODEL FIT Loglikelihood H0 Value -10317.360 Information Criteria Number of Free Parameters 22 Akaike (AIC) 20678.719 Bayesian (BIC) 20775.451 Sample-Size Adjusted BIC 20705.607 (n* = (n + 2) / 24) Entropy 0.830 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASSES BASED ON THE ESTIMATED MODEL Latent Classes 1 194.55844 0.32426 2 153.04166 0.25507 3 252.39990 0.42067 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASS PATTERNS BASED ON ESTIMATED POSTERIOR PROBABILITIES Latent Classes 1 194.55849 0.32426 2 153.04160 0.25507 3 252.39991 0.42067 CLASSIFICATION OF INDIVIDUALS BASED ON THEIR MOST LIKELY LATENT CLASS MEMBERSHIP Class Counts and Proportions Latent Classes 1 197 0.32833 2 154 0.25667 3 249 0.41500 Average Latent Class Probabilities for Most Likely Latent Class Membership (Row) by Latent Class (Column) 1 2 3 1 0.940 0.000 0.060 2 0.000 0.913 0.087 3 0.038 0.050 0.912 MODEL RESULTS Estimates S.E. Est./S.E. Latent Class 1 Means READ 41.735 0.477 87.542 WRITE 42.703 0.962 44.395 MATH 43.178 0.516 83.651 SCI 42.160 0.663 63.627 SS 43.848 0.695 63.101 Variances READ 32.996 2.820 11.700 WRITE 42.370 3.775 11.224 MATH 34.562 2.422 14.269 SCI 38.395 2.714 14.146 SS 53.884 3.850 13.996 Latent Class 2 Means READ 63.645 0.948 67.120 WRITE 61.193 0.453 135.171 MATH 62.610 0.865 72.405 SCI 61.648 0.667 92.453 SS 61.232 0.758 80.762 Variances READ 32.996 2.820 11.700 WRITE 42.370 3.775 11.224 MATH 34.562 2.422 14.269 SCI 38.395 2.714 14.146 SS 53.884 3.850 13.996 Latent Class 3 Means READ 52.618 0.925 56.872 WRITE 54.507 0.727 74.942 MATH 52.008 0.834 62.324 SCI 53.172 0.835 63.687 SS 52.794 0.808 65.328 Variances READ 32.996 2.820 11.700 WRITE 42.370 3.775 11.224 MATH 34.562 2.422 14.269 SCI 38.395 2.714 14.146 SS 53.884 3.850 13.996 Categorical Latent Variables Means C#1 -0.260 0.130 -2.010 C#2 -0.500 0.181 -2.767 QUALITY OF NUMERICAL RESULTS Condition Number for the Information Matrix 0.707E-02 (ratio of smallest to largest eigenvalue)
A 2 Class Latent Class Model Using Mplus
Data: File is D:\mplus\data\hsb6.dat ; Variable: Names are id gender race ses sch prog locus concept mot career read write math sci ss hiread hiwrite himath hisci hiss; Usevariables are hiread hiwrite himath hisci hiss; categorical = hiread hiwrite himath hisci hiss; classes = c(2); Analysis: Type=mixture; MODEL: %C#1% [hiread$1 *2 hiwrite$1 *2 himath$1 *2 hisci$1 *2 hiss$1 *2 ]; %C#2% [hiread$1 *-2 hiwrite$1 *-2 himath$1 *-2 hisci$1 *-2 hiss$1 *-2 ]; INPUT READING TERMINATED NORMALLY SUMMARY OF ANALYSIS Number of groups 1 Number of observations 600 Number of dependent variables 5 Number of independent variables 0 Number of continuous latent variables 0 Number of categorical latent variables 1 Observed dependent variables Binary and ordered categorical (ordinal) HIREAD HIWRITE HIMATH HISCI HISS Categorical latent variables C Estimator MLR Information matrix OBSERVED Optimization Specifications for the Quasi-Newton Algorithm for Continuous Outcomes Maximum number of iterations 1000 Convergence criterion 0.100D-05 Optimization Specifications for the EM Algorithm Maximum number of iterations 500 Convergence criteria Loglikelihood change 0.100D-06 Relative loglikelihood change 0.100D-06 Derivative 0.100D-05 Optimization Specifications for the M step of the EM Algorithm for Categorical Latent variables Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Optimization Specifications for the M step of the EM Algorithm for Censored, Binary or Ordered Categorical (Ordinal), Unordered Categorical (Nominal) and Count Outcomes Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Maximum value for logit thresholds 15 Minimum value for logit thresholds -15 Minimum expected cell size for chi-square 0.100D-01 Optimization algorithm EMA Random Starts Specifications Number of initial stage starts 10 Number of final stage starts 1 Number of initial stage iterations 10 Initial stage convergence criterion 0.100D+01 Random starts scale 0.500D+01 Random seed for generating random starts 0 Input data file(s) D:\mplus\data\hsb6.dat Input data format FREE SUMMARY OF CATEGORICAL DATA PROPORTIONS HIREAD Category 1 0.475 Category 2 0.525 HIWRITE Category 1 0.460 Category 2 0.540 HIMATH Category 1 0.503 Category 2 0.497 HISCI Category 1 0.473 Category 2 0.527 HISS Category 1 0.352 Category 2 0.648 THE MODEL ESTIMATION TERMINATED NORMALLY TESTS OF MODEL FIT Loglikelihood H0 Value -1677.276 Information Criteria Number of Free Parameters 11 Akaike (AIC) 3376.552 Bayesian (BIC) 3424.918 Sample-Size Adjusted BIC 3389.996 (n* = (n + 2) / 24) Entropy 0.828 Chi-Square Test of Model Fit for the Binary and Ordered Categorical (Ordinal) Outcomes Pearson Chi-Square Value 54.151 Degrees of Freedom 20 P-Value 0.0001 Likelihood Ratio Chi-Square Value 51.429 Degrees of Freedom 20 P-Value 0.0001 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASSES BASED ON THE ESTIMATED MODEL Latent Classes 1 331.61601 0.55269 2 268.38399 0.44731 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASS PATTERNS BASED ON ESTIMATED POSTERIOR PROBABILITIES Latent Classes 1 331.61545 0.55269 2 268.38455 0.44731 CLASSIFICATION OF INDIVIDUALS BASED ON THEIR MOST LIKELY LATENT CLASS MEMBERSHIP Class Counts and Proportions Latent Classes 1 334 0.55667 2 266 0.44333 Average Latent Class Probabilities for Most Likely Latent Class Membership (Row) by Latent Class (Column) 1 2 1 0.958 0.042 2 0.044 0.956 MODEL RESULTS Estimates S.E. Est./S.E. Latent Class 1 Thresholds HIREAD$1 -1.894 0.215 -8.811 HIWRITE$1 -1.525 0.182 -8.365 HIMATH$1 -1.339 0.169 -7.940 HISCI$1 -1.599 0.168 -9.507 HISS$1 -2.006 0.199 -10.054 Latent Class 2 Thresholds HIREAD$1 2.201 0.296 7.430 HIWRITE$1 1.434 0.181 7.901 HIMATH$1 1.888 0.224 8.436 HISCI$1 1.738 0.242 7.181 HISS$1 0.574 0.145 3.953 Categorical Latent Variables Means C#1 0.212 0.108 1.955 RESULTS IN PROBABILITY SCALE Latent Class 1 HIREAD Category 1 0.131 0.024 5.351 Category 2 0.869 0.024 35.574 HIWRITE Category 1 0.179 0.027 6.681 Category 2 0.821 0.027 30.689 HIMATH Category 1 0.208 0.028 7.487 Category 2 0.792 0.028 28.554 HISCI Category 1 0.168 0.024 7.150 Category 2 0.832 0.024 35.363 HISS Category 1 0.119 0.021 5.687 Category 2 0.881 0.021 42.262 Latent Class 2 HIREAD Category 1 0.900 0.027 33.878 Category 2 0.100 0.027 3.749 HIWRITE Category 1 0.807 0.028 28.625 Category 2 0.193 0.028 6.824 HIMATH Category 1 0.869 0.026 33.994 Category 2 0.131 0.026 5.143 HISCI Category 1 0.850 0.031 27.621 Category 2 0.150 0.031 4.860 HISS Category 1 0.640 0.033 19.119 Category 2 0.360 0.033 10.771 ODDS RATIO RESULTS Latent Class 1 Compared to Latent Class 2 HIREAD Category > 1 60.079 20.083 2.991 HIWRITE Category > 1 19.269 4.750 4.057 HIMATH Category > 1 25.208 6.675 3.776 HISCI Category > 1 28.112 7.882 3.566 HISS Category > 1 13.189 3.164 4.168 QUALITY OF NUMERICAL RESULTS Condition Number for the Information Matrix 0.736E-01 (ratio of smallest to largest eigenvalue)
A 3 Class Latent Class Model Using Mplus
Data: File is D:\mplus\data\hsb6.dat ; Variable: Names are id gender race ses sch prog locus concept mot career read write math sci ss hiread hiwrite himath hisci hiss; Usevariables are hiread hiwrite himath hisci hiss; categorical = hiread hiwrite himath hisci hiss; classes = c(3); Analysis: Type=mixture; MODEL: %C#1% [hiread$1 *2 hiwrite$1 *2 himath$1 *2 hisci$1 *2 hiss$1 *2 ]; %C#2% [hiread$1 *0 hiwrite$1 *0 himath$1 *0 hisci$1 *0 hiss$1 *0 ]; %C#3% [hiread$1 *-2 hiwrite$1 *-2 himath$1 *-2 hisci$1 *-2 hiss$1 *-2 ]; INPUT READING TERMINATED NORMALLY SUMMARY OF ANALYSIS Number of groups 1 Number of observations 600 Number of dependent variables 5 Number of independent variables 0 Number of continuous latent variables 0 Number of categorical latent variables 1 Observed dependent variables Binary and ordered categorical (ordinal) HIREAD HIWRITE HIMATH HISCI HISS Categorical latent variables C Estimator MLR Information matrix OBSERVED Optimization Specifications for the Quasi-Newton Algorithm for Continuous Outcomes Maximum number of iterations 1000 Convergence criterion 0.100D-05 Optimization Specifications for the EM Algorithm Maximum number of iterations 500 Convergence criteria Loglikelihood change 0.100D-06 Relative loglikelihood change 0.100D-06 Derivative 0.100D-05 Optimization Specifications for the M step of the EM Algorithm for Categorical Latent variables Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Optimization Specifications for the M step of the EM Algorithm for Censored, Binary or Ordered Categorical (Ordinal), Unordered Categorical (Nominal) and Count Outcomes Number of M step iterations 1 M step convergence criterion 0.100D-05 Basis for M step termination ITERATION Maximum value for logit thresholds 15 Minimum value for logit thresholds -15 Minimum expected cell size for chi-square 0.100D-01 Optimization algorithm EMA Random Starts Specifications Number of initial stage starts 10 Number of final stage starts 1 Number of initial stage iterations 10 Initial stage convergence criterion 0.100D+01 Random starts scale 0.500D+01 Random seed for generating random starts 0 Input data file(s) D:\mplus\data\hsb6.dat Input data format FREE SUMMARY OF CATEGORICAL DATA PROPORTIONS HIREAD Category 1 0.475 Category 2 0.525 HIWRITE Category 1 0.460 Category 2 0.540 HIMATH Category 1 0.503 Category 2 0.497 HISCI Category 1 0.473 Category 2 0.527 HISS Category 1 0.352 Category 2 0.648 IN THE OPTIMIZATION, ONE OR MORE LOGIT THRESHOLDS APPROACHED AND WERE SET AT THE EXTREME VALUES. EXTREME VALUES ARE -15.000 AND 15.000. THE FOLLOWING THRESHOLDS WERE SET AT THESE VALUES: * THRESHOLD 1 OF CLASS INDICATOR HIWRITE FOR CLASS 3 AT ITERATION 65 THE MODEL ESTIMATION TERMINATED NORMALLY TESTS OF MODEL FIT Loglikelihood H0 Value -1661.060 Information Criteria Number of Free Parameters 17 Akaike (AIC) 3356.120 Bayesian (BIC) 3430.867 Sample-Size Adjusted BIC 3376.897 (n* = (n + 2) / 24) Entropy 0.675 Chi-Square Test of Model Fit for the Binary and Ordered Categorical (Ordinal) Outcomes Pearson Chi-Square Value 17.791 Degrees of Freedom 14 P-Value 0.2165 Likelihood Ratio Chi-Square Value 18.996 Degrees of Freedom 14 P-Value 0.1651 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASSES BASED ON THE ESTIMATED MODEL Latent Classes 1 220.03955 0.36673 2 197.52264 0.32920 3 182.43781 0.30406 FINAL CLASS COUNTS AND PROPORTIONS FOR THE LATENT CLASS PATTERNS BASED ON ESTIMATED POSTERIOR PROBABILITIES Latent Classes 1 220.03954 0.36673 2 197.52262 0.32920 3 182.43784 0.30406 CLASSIFICATION OF INDIVIDUALS BASED ON THEIR MOST LIKELY LATENT CLASS MEMBERSHIP Class Counts and Proportions Latent Classes 1 229 0.38167 2 175 0.29167 3 196 0.32667 Average Latent Class Probabilities for Most Likely Latent Class Membership (Row) by Latent Class (Column) 1 2 3 1 0.905 0.094 0.001 2 0.072 0.818 0.110 3 0.000 0.168 0.832 MODEL RESULTS Estimates S.E. Est./S.E. Latent Class 1 Thresholds HIREAD$1 3.031 0.554 5.475 HIWRITE$1 1.596 0.270 5.902 HIMATH$1 2.202 0.321 6.869 HISCI$1 2.580 0.488 5.284 HISS$1 0.754 0.194 3.894 Latent Class 2 Thresholds HIREAD$1 -0.656 0.303 -2.162 HIWRITE$1 -0.116 0.504 -0.230 HIMATH$1 -0.105 0.274 -0.384 HISCI$1 -0.937 0.318 -2.943 HISS$1 -1.049 0.340 -3.084 Latent Class 3 Thresholds HIREAD$1 -3.134 1.336 -2.346 HIWRITE$1 -15.000 0.000 0.000 HIMATH$1 -2.815 1.340 -2.100 HISCI$1 -1.895 0.488 -3.884 HISS$1 -2.833 0.625 -4.532 Categorical Latent Variables Means C#1 0.187 0.256 0.732 C#2 0.079 0.483 0.165 RESULTS IN PROBABILITY SCALE Latent Class 1 HIREAD Category 1 0.954 0.024 39.239 Category 2 0.046 0.024 1.893 HIWRITE Category 1 0.831 0.038 21.940 Category 2 0.169 0.038 4.449 HIMATH Category 1 0.900 0.029 31.321 Category 2 0.100 0.029 3.465 HISCI Category 1 0.930 0.032 29.083 Category 2 0.070 0.032 2.203 HISS Category 1 0.680 0.042 16.146 Category 2 0.320 0.042 7.600 Latent Class 2 HIREAD Category 1 0.342 0.068 5.005 Category 2 0.658 0.068 9.646 HIWRITE Category 1 0.471 0.125 3.755 Category 2 0.529 0.125 4.216 HIMATH Category 1 0.474 0.068 6.938 Category 2 0.526 0.068 7.708 HISCI Category 1 0.282 0.064 4.375 Category 2 0.718 0.064 11.160 HISS Category 1 0.259 0.065 3.971 Category 2 0.741 0.065 11.335 Latent Class 3 HIREAD Category 1 0.042 0.053 0.781 Category 2 0.958 0.053 17.940 HIWRITE Category 1 0.000 0.000 0.000 Category 2 1.000 0.000 0.000 HIMATH Category 1 0.057 0.071 0.791 Category 2 0.943 0.071 13.202 HISCI Category 1 0.131 0.055 2.357 Category 2 0.869 0.055 15.686 HISS Category 1 0.056 0.033 1.694 Category 2 0.944 0.033 28.795 ODDS RATIO RESULTS Latent Class 1 Compared to Latent Class 2 HIREAD Category > 1 0.025 0.015 1.647 HIWRITE Category > 1 0.181 0.121 1.491 HIMATH Category > 1 0.100 0.045 2.206 HISCI Category > 1 0.030 0.017 1.746 HISS Category > 1 0.165 0.071 2.317 Latent Class 1 Compared to Latent Class 3 HIREAD Category > 1 0.002 0.003 0.700 HIWRITE Category > 1 0.000 0.000 999.000 HIMATH Category > 1 0.007 0.009 0.722 HISCI Category > 1 0.011 0.007 1.589 HISS Category > 1 0.028 0.019 1.471 Latent Class 2 Compared to Latent Class 3 HIREAD Category > 1 0.084 0.119 0.706 HIWRITE Category > 1 0.000 0.000 999.000 HIMATH Category > 1 0.067 0.088 0.753 HISCI Category > 1 0.383 0.274 1.399 HISS Category > 1 0.168 0.120 1.395 QUALITY OF NUMERICAL RESULTS Condition Number for the Information Matrix 0.314E-02 (ratio of smallest to largest eigenvalue)
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Phil Ender, 24apr03