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Hi Qasim, You'd need a repeated-measures ANOVA (1 factor with 3 levels within-subject, 1 factor with 4 levels (groups) between-subjects). Another option, perhaps simpler, is to go with the 1 factor and 4 levels as in the link, and use as input differences between before and after. This can be done up to 3 times (post-pre, 4mo-pre, 4mo-post), and these can be combined with NPC. Generally speaking, NPC tends to be more powerful than a repeated measures ANOVA, and that's the route I'd take. Even without the combination, running 3 separate smaller designs will be faster than just one big repeated measures design. All the best, Anderson On 14 June 2018 at 07:39, Qasim Bukhari <[log in to unmask]> wrote: > Dear all, > We have a question regarding design matrix. We have 4 groups: sham, > waiting list, Drug1 and Drug2. Each group has 3 session 3 in the scanner: > pre, post and after 4 months. There are different subjects in each group, > but the subjects are same within sessions. > I originally thought that a two sample paired t test would be best suited > and I can test each session at a time for pre vs post. And if something > is found significant in for example group 1 pre vs post and not significant > in control group pre vs post, then i can consider it significant. However I > have just realised that probably a better approach would be to use a 1 > factor 4 level anova as described here. Is that the correct design matrix ? > But here, the example considers 8 subjects, that means at each level there > is a different subject. > My question is, was my previous approach correct or should I follow the 1 > factor 4 level approach as described below ? > > https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/GLM#ANOVA:_1-factor_ > 4-levels__.281-way_between-subjects_ANOVA.29 > GLM - FslWiki > <https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/GLM#ANOVA:_1-factor_4-levels__.281-way_between-subjects_ANOVA.29> > Experimental Designs - No repeated measures. We start considering only > designs where there is one scan per subject, that is, no repeated measures. > fsl.fmrib.ox.ac.uk > Any help will be very appreciated > > Thanks and best > Qasim > > > ------------------------------ > > To unsubscribe from the FSL list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1 > ######################################################################## To unsubscribe from the FSL list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=FSL&A=1