Juergen Haenggi wrote:
Dear Freesurfer users
I am trying to create the GroupDescriptorFile 1 for an ANCOVA in order to analyze local cortical thickness. I intend to compare two groups while controlling for age and mean cortical thickness.
Am I right that I can leave out the term "class" and model group as a variable?
Nope, you have to model it as a class. Class actually allows modeling of both the intercept and slope separately for each group.
GroupDescriptorFile 1 Title CorticalThickness Variables Group Age MeanThickness Input Control01 ControlSubject 27 3.14 Input Control02 ControlSubject 31 3.28 ....
Does the variables all have to be integers or can it be also a string?
Variables must be integers or decimals, they cannot be strings. The "Variables" represent continuous values such as age, IQ, etc. Whereas the classes represent *combinations* of discrete variables such as group membership, gender, etc.
doug
Thanks for helping Best regards Juergen
Juergen Haenggi Ph.D. (Dr. des.) Division of Neuropsychology Institute of Psychology University of Zurich Binzmuehlestrasse 14, PO Box 25 8050 Zurich, Switzerland 0041 44 635 73 97 (phone office) 0041 76 445 86 84 (phone mobile) 0041 44 635 74 09 (fax office) BIN 4.D.04 (office room number) j.haenggi@psychologie.uzh.ch (email) http://www.psychologie.uzh.ch/neuropsy/ (website) http://www.juergenhaenggi.ch (private website)
Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer