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Mplus Discussion > Structural Equation Modeling >
 ben kübler posted on Tuesday, May 06, 2008 - 9:57 am

is M+ using a one dimensional T-Test or an two dimensional?
 Linda K. Muthen posted on Tuesday, May 06, 2008 - 12:32 pm
If you are talking about the ratio of the parameter estimate to the standard error of the parameter estimate in column three of the results, this is a univariate z-test.
 ben kübler posted on Wednesday, May 07, 2008 - 4:23 am
Yes, i mean the tird column of the Results from the Structural Model "SEM" with the command
"Factor on Factor" which shows the significance for the Path.
In LISREL its used a T-Test so we thought in M+ its used the same Test?
 Linda K. Muthen posted on Wednesday, May 07, 2008 - 6:51 am
They call it a t-test in LISREL. It is really an approximate z-test just like in Mplus.
 ben kübler posted on Tuesday, May 13, 2008 - 7:11 am
Tank you for this informations.
So I have to use a t-value or z-value table?
 Linda K. Muthen posted on Tuesday, May 13, 2008 - 7:38 am
You would use a z-test table.
 Michael Strambler posted on Tuesday, August 24, 2010 - 7:16 am
I am interested in conducting a simple paired t-test (comparing time1 to time2 on the same variable) while using FIML to handle the missing data. However, I have not been able to find documentation on how to achieve this in Mplus. Is this possible in Mplus? Thank you.
 Linda K. Muthen posted on Tuesday, August 24, 2010 - 8:22 am
You can do this using MODEL TEST.

[y1] (p1);
[y2] (p2);

0 = p1 - p2;
 Michael Strambler posted on Tuesday, August 24, 2010 - 1:09 pm
Thank you very much. I just ran the data as you described. Can you provide some guidance on the values in the output that I should be using to determine whether the pairs are significantly different? Thanks again.
 Linda K. Muthen posted on Tuesday, August 24, 2010 - 2:51 pm
In the results where fit statistics are given, you will find the results under Wald Test of Parameter Constraints. The null hypothesis is that the parameters are equal. If your p-value is greater than .05, you cannot reject this hypothesis.
 Jonathan posted on Thursday, November 07, 2013 - 12:44 pm
Hi there:

I know that I can use MODEL TEST to run a Wald test, which is an omnibus test to see if coefficients are different than each other. So I could run--

0 = a1-a2;
0 = a2-a3;
0 = a3-4;

To see if any of the relationships I specified are different (please correct me on this if I am wrong).

I would like to test to see if *each* relationship is different from each other. So I would like to run something similar to this, but to get separate output for each contrast that I specify. So on the output, I would hopefully have one test statistic for the a1-a2 contrast; another for a2-a3 contrast; etc.

Is this possible in MPlus? Thank you for your time.
 Linda K. Muthen posted on Thursday, November 07, 2013 - 1:16 pm
The test you shows above tests all effects together. You would need to run them one at a time if you want separate tests. Alternatively, you could create new parameters in MODEL CONSTRAINT for each difference and you will get a z-test for each one.
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