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Hi Michelle, Please see below: On 25 October 2016 at 16:50, Michelle VanTieghem < [log in to unmask]> wrote: > Hi Anderson, > > Thanks for this model! To clarify the statistics underlying this model, is > this performing a mixed effects model for the 2(between) x 3(within) > interaction, or a repeated measures ANOVA? > These names don't really help much. The best is to show the designs. In any case, the first is testing only within-subject effects, including the interaction, which is also a within-subject effect, whereas the second is testing between-subject effects. It uses repeated measurements. It is an analysis of variance. > > I have a couple of questions regarding the implementation of this model in > PALM, since I have not used PALM before. The design.ods you provided > actually contains 2 separate files, and each of those files includes the > design.mat and design.con for (a) the 2x3 interaction and (b) the main > effect of group across all 3 conditions. > Exactly. > > (1) I cannot find an example in PALM user information where one can enter > 2 separate design.mats and design.cons into the same command. Are they > supposed to be entered as separate files, or is there a way to combine the > files in a way that will perform both models simultaneously? > Use something as: palm -i data.nii -d design1.mat -t design1.con -d design2.mat -t design2.con -eb blocks.csv -whole -within -corrcon [...] > > (2) The EB column represents the exchangability blocks, within subjects. > In the example provided, there should be a separate "blocks.csv" file input > for the PALM command. [[palm -i modality1_4d.nii -d design.mat -t > design.con -eb blocks.csv]] What is supposed to go into the blocks.csv > file? If the EBs are already included within my design.mat file, do I also > need a blocks.csv file? > Yes. > > (3) I have not added F-tests to a design.con file before (only in the > GUI). Is this already in the appropriate format such that the F-test is > indicated by the final column in the design.con file, and the rows with no > F-test indicated are just empty? > You can ignore the F-tests shown in the design. Use instead the option -corrcon. If however you were to create them, they are specified as .fts files in the same way as in randomise or FEAT. > > (4) I would also like to include covariates of sex and Age (continuous). > Can you advise how to modify this design to account for continuous > covariates? Are they just added as separate EVs within the design.mat file? > If age and sex don't change between the 3 measurements per subject, these don't need to be entered in design1, as the subject-specific EVs already account for that. For design2, you can add extra EVs for age and sex. > > (5) In addition, I would like to run a separate model to test the Age x > Group x Emotion interaction. Is it possible to test a 3-way interaction > with a continuous variable within this model framework in PALM? > Yes, it is. Please see design3 here: https://dl.dropboxusercontent.com/u/ 2785709/outbox/mailinglist/design_michelle.ods Design1 and design2 are the same. All the best, Anderson