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Re: REPEATED MIXED MODELS-post hoc tests/contrasts

Posted by Alexandra on Dec 29, 2014; 11:07am
URL: http://spssx-discussion.165.s1.nabble.com/REPEATED-MIXED-MODELS-post-hoc-tests-contrasts-tp5728007p5728292.html

Hello,

Yes, if I use the mixed menu command that would be the resulting output.  Thatʹs the syntax I wrote directly, that‘s why there arentʹt any other specifications. With your syntax I did the analysis but with the unstructured covariance,

MIXED LSRT BY LISTLENGTH gender WITH anx 
  /CRITERIA=CIN(95) MXITER(100) MXSTEP(10) SCORING(1) SINGULAR(0.000000000001) HCONVERGE(0, ABSOLUTE) LCONVERGE(0, ABSOLUTE) PCONVERGE(0.000001, ABSOLUTE) 
  /FIXED=LISTLENGTH gender anx LISTLENGTH*anx | SSTYPE(3) 
  /METHOD=ML 
  /PRINT=SOLUTION TESTCOV 
  /RANDOM=INTERCEPT | SUBJECT(COD_subiect) COVTYPE(UN) 
  /EMMEANS=TABLES(LISTLENGTH) COMPARE ADJ(BONFERRONI) 
  /EMMEANS=TABLES(gender) COMPARE ADJ(BONFERRONI).


 The resulting output shows only sign anxiety effect and interaction, and with list length as a fixed factor I obtain an unsignificant result. Which unfortunately undermines the effect of the interaction because without a sign list length effect there isn't an explanation why the interaction is sign (only with harder list lengths anxiety will have a detrimental effect). However only when I add anxiety the effect of list length becomes insign.

This is the output. Should I use a dummy variable for coding the three levels of list length (L1, L2,L3)? how should I interpret an interaction with three levels when LL3 x anx is set to zero?

   

 Parameter                                  b        SE           t              Sig.

 Intercept                               -25,5        297,8     -,086      ,932

[LISTLENGTH=1]                   473,5      306,6       1,5        ,124

[LISTLENGTH=2]                   597,2      306,7       1,9        ,053

[LISTLENGTH=3]                     0a             0             .              .

[gender=1]                               309.2       99.5         3.1        .002
[gender=2]                                0a              0             .              .

 anx                                           44,9        8.5          5.2       0.00

[LISTLENGTH=1] * anx         -28,2       8,8          -3,1        ,002

[LISTLENGTH=2] * anx         -25,6        8,8          -2,8        ,004

[LISTLENGTH=3] * anx         0a         0              .                   .

 a. This parameter is set to zero because it is redundant.

b. Dependent Variable: LSRT.

Thanks a lot again for all your help!
Alexandra



On 12/2/14, Maguin, Eugene [via SPSSX Discussion] <[hidden email]> wrote:

>
>
> You began with data in wide format (something like):
>
> id1 anxiety ls1 ls2 ls3.
>
> I know you are working on menus but the listing should show a varstocases
> command with these elements, although it may have others in addition.
>
> varstocases make ls from ls1 to ls3/index=listlength.
>
> The resulting file WILL have anxiety in it. Specifically the structure will
> be
>
> Id1 anxiety listlength ls
>
> Your basic mixed command will have these elements
>
> mixed ls by listlength with anxiety/fixed=listlength