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şeyma posted on Tuesday, March 11, 2014 - 8:57 am
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Dear Mplus users, 1. I am trying to running example 10.5 monte carlo study. But I want this data include a covariate variable. (for example a gender variable: 600 females in latent class 1, 400 males in latent class 2; 400 females in latent class 2 and 600 males in latent class 1=2000 observations totaly gender splşt is 50% and . How can I add such a variable in this study? 2. Another question is: Which prior paramter used for this simulation study? Can we generate response patterns in this example based on item response model? Because I want to item diffuculties differ between latent classes. Thank you. Şeyma |
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First, note that this is an advanced analysis that calls for experience with Mplus Monte Carlo simulations. 1. You add a binary x variable (see UG chapter 11 for how to do that) which influences the latent class variable ("c ON x"). 2. You can use parameter values from a real-data analysis. |
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şeyma posted on Tuesday, April 08, 2014 - 4:34 am
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Dear Bengt Muthen, I try to fit my data to the multilevel mixture item response model. For this reason I used example 10.5. I guess the syntax is for 1-PL model or Rasch model. I have now class spesicific item diffuculties. I want to use these parameter for differential item functioning detection. But I wonder that these item diffuculties directly comparable? Should I bring the parameters the same scale? Thanks, Şeyma |
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Ex 10.5 uses a 2PL model. To have a comparable latent variable scale you need to start with equality of loadings and thresholds across the classes. Then you can free up some of those equalities to capture DIF. |
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şeyma posted on Thursday, September 18, 2014 - 2:39 am
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Dear Muthen, For multilevel mixture irt model I generated the data in C#. I generated two student latent classes and two school latent classes. The diffuculty parameters differ across student latent classes, so I generate 20 diffuculty parameters for student class one and 20 parameters for student class two. For dif detection, Student class 1 school class 1 ,I use the first 20 diffuculty parameters. Student class 1 school class 2, I use the first 20 diffuculty parameters but only some of them differ. Student class 2 school class 1 I use second 20 diffuculty parameters. Student class 2 school class 2 I use second 20 diffuculty parameters but only some of them differ. For analyzing the simulated data I use example 10.5. I wonder that in output the threshols are so. 1 1;1 2; 2 1 and 2 2. Which is school class and which is student class. How is the order? In my output 1 1 and 2 2 were almost same estimated.. And 1 2 and 2 1 were almost same estimated. |
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The order of the thresholds corresponds to the order of the categorical latent variables in the CLASSES statement. |
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Xiaorui posted on Thursday, December 03, 2015 - 5:30 pm
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Dear Dr Muthen, Is there anyway to simulate a multilevel IRT model and run the simulation data using single level IRT simultaneously? Thanks! Xiaorui |
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You would need to do this in two steps. First generate and save the data. Second, analyze the date using TYPE=MONTECARLO. |
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