Let's say I have a variable with 6 levels, for example, different tasks which are just a subset of all possible tasks. I am interested in differences between the tasks so should add it as a fixed effect, but I might also want to take into account random differences among the tasks.

Doesn't it make sense to include task as a fixed effect as well as a random effect? I suspect it doesn't, according to some posts I read in CV, but how can I account for random differences among the tasks that are not induced by any experimental manipulation. Is this even possible in mixed models?

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Browse other questions tagged or ask your own question.