help > RE: 2x3 Mixed Design ANOVA
Mar 13, 2019  03:03 AM | Andrew Zalesky
RE: 2x3 Mixed Design ANOVA
Hi Ana,

To add a covariate, simply add an additional column to your design matrix that contains that covariate.

Then add a zero to your contrast vector to indicate that it is a covariate of no interest.

Andrew


Originally posted by Ana Coelho:
Hi Dr. Zalesky,

In this repeated measures design (3 timepoints and 2 groups) is it possible to include covariates?


Thanks in advance!
Ana 

Originally posted by Andrew Zalesky:
Hi Ana,

I forgot that your design is a repeated measures design. If you are only interested in the group effect, a repeated measures design is not necessary. You can either run a between-group t-test for each time point or first average your data across time points and perform a single t-test of the between-group difference.

What you might be interested in testing for the current repeated measures design is the interaction between group and time. Assuming that the first 8 subjects are group 1 and the last 8 subjects are group 2, the design matrix would look like this:


 1 1
 2 2
 4 4
 1 1
 2 2
 4 4
 1 -1
 2 -2
 4 -4
 1 -1
 2 -2
 4 -4

Once again, you will need to add additional columns (one for each subject) to model within-subject effects.




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Ana Coelho Oct 10, 2018
Andrew Zalesky Oct 10, 2018
Ana Coelho Oct 11, 2018
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Andrew Zalesky Oct 15, 2018
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Andrew Zalesky Oct 18, 2018
Ana Coelho Mar 12, 2019
RE: 2x3 Mixed Design ANOVA
Andrew Zalesky Mar 13, 2019
Ana Coelho Mar 13, 2019
Ana Coelho Oct 19, 2018
Ana Coelho Oct 22, 2018
Andrew Zalesky Oct 22, 2018
Ana Coelho Oct 25, 2018
Andrew Zalesky Oct 25, 2018
Ana Coelho Oct 26, 2018
Andrew Zalesky Oct 26, 2018