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CMP posted on Friday, January 09, 2015 - 3:32 am
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I am planning a study where I would use latent class profiling to identify different classes (preferably two) and include these classes as a covariate in a CFA with two factors (each having 3 indicators). I want to calculate the minimum required sample size using the not-close-fit hypothesis approach. Question: I would like to know if I should include the indicators of the latent class when counting my free parameters for determining the df of the model. |
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Seems like you need to do a Monte Carlo study to get this power so I don't know what you would use the df for. |
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CMP posted on Monday, January 12, 2015 - 1:16 pm
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Thank you for your response. Following your advice, I attempted to do a Monte Carlo study. However, I got error messages which I don't understand. Below are the error messages received: ------------- *** ERROR in MODEL command One or more pairs of ordered thresholds are not increasing in Class 2. Check your starting values. Problem with the following pairs: Y3$2 (1.000) and Y3$3 (-0.120) Y5$1 (0.307) and Y5$2 (0.000) Y6$1 (0.307) and Y6$2 (0.150) *** ERROR in MODEL POPULATION command One or more pairs of ordered thresholds are not increasing in Class 1. Check your population values. Problem with the following pairs: Y3$1 (0.000) and Y3$2 (0.000) Y3$2 (0.000) and Y3$3 (-0.250) Y5$1 (0.000) and Y5$2 (0.000) *** ERROR in MODEL POPULATION command One or more pairs of ordered thresholds are not increasing in Class 2. Check your population values. Problem with the following pairs: Y3$1 (0.000) and Y3$2 (0.000) Y3$2 (0.000) and Y3$3 (-0.120) Y5$1 (0.000) and Y5$2 (0.000) |
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CMP posted on Monday, January 12, 2015 - 1:17 pm
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The syntax used was: MONTECARLO: NAMES ARE u y1-y14; NOBSERVATIONS = 500; NREPS = 500; SEED = 4533; GENERATE = y1 (1) y2 (1) y3(3) y4 (1) y5(2) y6 (2); CATEGORICAL = y1-y6; GENCLASSES = c (2); CLASSES = c (2); PATMISS = y7(.2) y8(.1) y9(.2) y10(.1) y11(.3) y12(.1) y13(.2) y14(.1) y11| y13(.2) y14(.2); PATPROBS = .4 | .6; MODEL POPULATION: %OVERALL% f1 BY y7-y12*.6; y13 ON u*.10; y14 ON u*.15; %c#1% [y1$1*.26 y2$1*.-30 y3$3*-.25 y4$1*.26 y5$2*.-30 y6$2*.30]; %c#2% [y1$1*.12 y2$1*.15 y3$3*-.12 y4$1*.13 y5$2*.-15 y6$2*.15]; ANALYSIS: TYPE = MIXTURE; MODEL: %OVERALL% f1 BY y7-y12*.6; y13 ON u*.10; y14 ON u*.15; %c#1% [y1$1*.26 y2$1*.-30 y3$3*-.25 y4$1*.26 y5$2*.-30 y6$2*.30]; %c#2% [y1$1*.12 y2$1*.15 y3$3*-.12 y4$1*.13 y5$2*.-15 y6$2*.15]; OUTPUT: TECH9; |
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Please don't post in more than one window as requested. When you have a variable such as y3 with 3 thresholds you need to give population values for all 3 thresholds, not just the highest one. And the values need to be ordered from low to high (so not the same). |
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CMP posted on Wednesday, January 14, 2015 - 4:37 am
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My sincere aplogies. Thank you for your response. I took it into account but got another error message: *** FATAL ERROR THE POPULATION COVARIANCE MATRIX THAT YOU GAVE AS INPUT IS NOT POSITIVE DEFINITE AS IT SHOULD BE. How can I address this problem? Thanking you in advance for your help. |
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Check that you have given population parameter values for all parameters. If you don't, they are zero. Zero variances is one cause of this message. |
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CMP posted on Wednesday, January 14, 2015 - 6:50 am
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Thank so much for this helpful information. I can't identify where I got it wrong. Please could you point me to the omission? Many thanks! MODEL POPULATION: %OVERALL% f1 BY y7@1 y8-y12*.6; f1*.5;! f1 variance is .5 y8-y12*.4; f1 WITH y13*.3; f1 WITH y14*.3; !y13 ON c*.10; !y14 ON c*.15; %c#1% [y1$1*.26 y2$1*-.3 y3$1*-.25 y3$2*.5 y3$3*1 y4$1*.26 y5$1*-.3 y5$2*.8 y6$1*.3 y6$2*.5]; %c#2% [y1$1*.26 y2$1*-.3 y3$1*-.25 y3$2*.5 y3$3*1 y4$1*.26 y5$1*-.3 y5$2*.8 y6$1*.3 y6$2*.5]; |
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Please send input, output, and license number to Support. |
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CMP posted on Wednesday, January 14, 2015 - 11:19 am
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I will. I am so thankful for your help. |
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