Testing for an interaction effect with more than 1 ivar using depsamplesF

[Sander, Myriam]

Dear Fieldtrip-Users, 

 

I would like to test for an interaction effect in a within-subject
experiment. I know there was a similar question by Tzvetan Popov this
year, but I did not find an answer to his question in the archives, so I
would like to ask this again. 
  

 I have 5 subjects and 2 within-factors, one with 2 levels and one with
3 levels. 

I specified the design matrix as

 

1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2

1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3

 

clusterstatcfg.ivar   = [2,3];

clusterstatcfg.uvar   = 1;

 

I want to use freqstatistics with depsamplesF using montecarlo / cluster
as correction method, but I get the following error: 

Error using ==> statfun_depsamplesF at 110

Invalid specification of the design array.

 

The problem seems to me that depsamplesF only allows for 1 ivar, but not
two - is that right? 

 

Is there a way how to test interaction effects in this way? Or is it
necessary to first take the difference between the 2 levels of the first
factors and then only test for the effect of the second factor? 

 

Thanks a lot for your help, 

Myriam 

 

______________________________________

 

Myriam Sander, Dipl.-Psych.

Predoctoral Research Fellow

Center for Lifespan Psychology

Max Planck Institute for Human Development

Lentzeallee 94

14195 Berlin Germany

 

Office Phone: (49) 30-82406-414

Fax: (49) 30-8249939

 

sander at mpib-berlin.mpg.de <mailto:sander at mpib-berlin.mpg.de> 

______________________________________

 


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