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Dear Paul and Gregory, [Paul: > (sorry, slightly misunderstood your experimental design in my previous > response- Narender is quite correct that it's better to implcitly model the > 'baseline' task, i.e. not give it a separate column in the design matrix). > > I am interested however in your group by task interaction. A random effects > analysis is relevant to generalisation to the population, this is clearly > impossible (and not actually the question of interest) in a single case > study.] I assumed that Gregory had a pool of patients (perhaps Gregory could confirm)... [Gregory: >>My goal is to average my normal data and use that average to compare to each >>patient's brain. (ie average of 10 vs 1 patient)] It would clearly not be possible to conduct any sort of group analysis on an N of one subject!!! In any case, assuming that Gregory does indeed have a pool of patients with, presumably, some homogeneous characteristics and a common set of deficits, surely it would be more interesting and more meaningful to ask how the patient group as a whole responded differently to conditions A and B, compared to normals, after accounting for activity that is due to individual differences between subjects. In this instance, would it not be more appropriate to conduct an analysis fixed effects analysis? Narender Ramnani University Laboratory of Physiology, University of Oxford.