I'm trying to model a linear mixed effects model but whenever I tried to model interaction terms my model gives error about convergence. Although I tried to increase the number of iterations as possible solution I could not achieve to model interactions either. What are your suggestions about this?
With only main effects, my code works fine but ı need to interpret the interaction terms as well. Also I 'm not quite sure is it appropriate to model the fixed effects with only main effects, without interaction?
Any help would be greatly appreciated.
Thanks in advance!