Dear FSL experts,
I am trying to setup a design to compare three groups of subjects (two patient groups and controls) adjusting for different scanners (three) used during data acquisition. I want to include scanners as a covariates in a model as suggested earlier in few posts .
I found this solution but it deals with only two groups scenario:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind1501&L=FSL&P=R97017&1=FSL&9=A&J=on&d=No+Match%3BMatch%3BMatches&z=4
So I am thinking about following design:
EV1: 1 to code 1st group
EV2: 1 to code 2nd group
EV3: 1 to code 3rd group
EV4: 1 to code scanner 1 and 0 to code other scanners
EV5: 1 to code scanner 2 and 0 to code other scanners
EV6: 1 to code scanner 3 and 0 to code other scanners
Now, the questions are:
1) Is this design is ok?
2) Should I mean-center each of the “scanner” EVs?
Help will be greatly appreciated.
Best regards,
Chris
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