I am trying to carry out a linear mixed model but I have some problems with input of data. So, I ask for your help.
I want to establish two levels (level 1: subjects; level 2: schools (even level3: country; Spain Vs France), however I don’t know how to establish in the program these two levels of hierarchy. I mean, can I put the two variables (Id subjects and schools) in the initial box? If I can, then, how do I established the order in the model? Is it in the random effects where I can establish the differences for the concretely level?
After that, I have to set the fixed effects and the random effects. How can I establish the factors that I want for the second level? Do I have to click on the nested terms? If for example I want to know the existence of a significant effect of country, controlling the possible effect of the scholar centre, what do I have to do? Do I nest scholar centre into country in fixed factors? Or should I do that in random effects?
If I don’t click on the nested terms, all the effects affect to the first level? (In this cases subjects). Does it happen in two types of factors, fixed and random?
I hope I have been able to explain myself. This topic begins to be VERY complicated to me. I would thank any answer about it.