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fangfang posted on Wednesday, September 16, 2015 - 12:25 am
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Dear Dr. Muthen, I want to use the Wald chi-square test to test whether there are differences in the coefficients c1 and c2. I wrote a set of codes according the user guide. I want to know which code is the right one? It would be great if you could provide an appropriate example input code. I would be grateful for your help! Thanks in advance. The first, MODEL CONSTRAINT: New (c); MODEL TEST: c=c1-c2; the second, MODEL CONSTRAINT: New (c); c=c1-c2; MODEL TEST: c=0; |
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You use the labels from the MODEL command in MODEL CONSTRAINT and MODEL TEST. Neither is correct. MODEL: y ON x; MODEL male: y ON x (p1); MODEL female: y ON x (p2); MODEL TEST: 0 = p1 - p2; |
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fangfang posted on Wednesday, September 16, 2015 - 6:01 pm
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Thank you very much!Dr. Muthen. I am sorry for not making it clear. The model I want to run is the regression of two dependent variables (Y1, Y2) on one independent variable (X). MODEL: y1 ON x(p1); y2 ON x(p2); MODEL TEST: 0=p1-p2; is that right? thank you again! |
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The language is correct but you should do this only if y1 and y2 are measured on the same scale. |
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fangfang posted on Thursday, September 17, 2015 - 7:14 am
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Thank you for your prompt response! Dr.Muthen. In the model, y1 and y2 are two different types of one behavior (promotive voice and prohibitive voice). I don't understand what does "the same scale" mean. Do you mean that they are the same behavior measured in different samples? what should I do if I want to compare the cofficients of the regression of y1,y2 on x in the same sample? could you provide the code, please? Thank you very much! |
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Are the minimum and maximum values of the variables the same. If not, they should not be compared. You should look at their standardized coefficients. |
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fangfang posted on Thursday, September 17, 2015 - 7:31 pm
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Many thanks to you.Dr. Muthen. It is a test of the difference between coefficients for different dependent variables from a single sample. But, all items of variables are measured by a 7-point Likert-type scale. Given that,is it suitable to use the wald test? I am grategul for your help! |
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If both dependent variables are measured on the same scale, this is OK. |
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fangfang posted on Thursday, September 17, 2015 - 9:16 pm
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Thank you very much for your help!Dr. Muthen. |
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Hi Dr. Muthen, I'd like to use Wald Chi-square test to assess parameter quality using Bayesian estimator. However, Mplus 8 said it is impossible to do Wald with Bayes. Are there any alternatives? Thanks for your time Tommy |
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Regarding the above post, here is the output from Mplus, MODEL TEST is not available with ESTIMATOR=BAYES. |
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You can use Model Constraint to define a new parameter that is e.g. the difference between two parameters, so that gives you a test. But you can't test several such differences jointly. Model Test for Bayes is on our to-do list. |
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Hi, I am trying to compare two beta coeffients from the same model. I think I am missing a piece of the puzzle from the above... this is my input which is probably quite wrong: VARIABLE: NAMES ARE SEX IDENTITY MI SI LI SE DEP RAI; USEVARIABLES SE IDENTITY DEP MI SI LI; ANALYSIS: ESTIMATOR = ML; MODEL CONSTRAINT: NEW (misi); WALD = MI - SI; MODEL: WB by SE DEP; WB ON IDENTITY MI; WB ON IDENTITY SI; WB ON IDENTITY LI; MODEL misi: WB ON MI (P1); WB ON SI (P2); MODEL TEST: 0 = P1-P2; *** ERROR in MODEL command Unknown group name MISI specified in group-specific MODEL command. Thanks |
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See the UG index under Wald test. |
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Hi I'm testing a cross lagged panel model, I can not figure out what it is wrong with my syntax, the paths from pbs to bes are not significant so we are testing this model across gender I got a message THE STANDARD ERRORS OF THE MODEL PARAMETER ESTIMATES COULD NOT BE COMPUTED. THE MODEL MAY NOT BE IDENTIFIED. CHECK YOUR MODEL. PROBLEM INVOLVING THE FOLLOWING PARAMETER: Parameter 106, Group FEMALE: [ PBW1 ] THE CONDITION NUMBER IS -0.403D-10. THE ROBUST CHI-SQUARE COULD NOT BE COMPUTED. PbW3 on PbW2 EmW2; PbW2 on PbW1 emW1; EmW3 on EmW2; EmW2 on EmW1; PbW1 with EmW1; PbW2 with EmW2; PbW3 with EmW3; PbW1; PbW2; PbW3; EmW1; EmW2; EmW3; ! correlated residual errors over time HLPw1 with HLPw2 HLPw3; HLPw2 with HLPw3; CARw1 with CARw2 CARw3; CARw2 with CARw3; COGEMw1 with COGEMw2 COGEMw3; COGEMw2 with COGEMw3; EMODISw1 with EMODISw2 EMODISw3; EMODISw2 with EMODISw3; EMOCONw1 with EMOCONw2 EMOCONw3; EMOCONw2 with EMOCONw3; Model male: ! the only difference with the speficied model is this and i did the same for the females [PbW1]; [PbW2]; [PbW3]; [EmW1]; [EmW2]; [EmW3]; |
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Send your output to Support along with your license number. |
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The Wald estimate for male and female group for a particular path was significant. However, the path for both male and female models were non significant. How is this interpreteD? |
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Perhaps your first sentence refers to a difference between the male and female estimate in a joint analysis of the genders and your second sentence refers to separate gender analyses and testing against zero? |
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MODEL BOY: Y ON X (BOYA); MODEL GIRL: Y ON X (GIRLA); MODEL TEST: 0 = BOYA - GIRLA; This is the part of the syntax I'm referring to in my question. The model test produces a significant result suggesting that there is a difference in the predictor-mediator path. However, these paths for male model and female model are not significant themselves. Is such an outcome possible? |
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Yes this is possible. Think of this case: male est = -0.5 female est = +0.5 The distance between each of those estimates and zero is smaller (0.5) than the distance between the estimates (1.0). |
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I see. In this case, would I still interpret this as significant differences between groups? Even though the parameters for male and female individually are not significant? |
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Yes on both. |
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