####################################### Day 14: random effects, choosing models ####################################### 5 / 29 / 2015 Reading: * random versus fixed effect in neuroimaging literature ftp://193.62.66.20/spm/data/face_rfx/RFXabstract.pdf http://www.fil.ion.ucl.ac.uk/spm/doc/books/hbf2/pdfs/Ch12.pdf * a simple tutorial on cross validation http://www.autonlab.org/tutorials/overfit.html Day: * Recall t and F tests: what are they doing exactly. Where does my variability come from? - example within run (from previous course) - example random effect (between subjects). * Wait a second: What is a model exactly ? * I am choosing a very wrong model: Consequences on the results of t/F tests. * How do I know my model is - is not very wrong? the good, the bad, the ugly (reverse order) - the ugly: p-hacking. Let's try it. - the bad: use R2. - the good: model validation * Model validation: Principle. Example of "random effect" model testing the effect of "grumpiness".