Could I use maximum likelihood method or any other frequenist method to estimate parameters for 3-level hierarchical model? Is there any references help me in this case? Thank you
You can fit a mixed model with three levels, or more, with
lme4. There's not a lot mentioned in their vignette. You need the
: operator. Here is a link to a tutorial: http://rpsychologist.com/r-guide-longitudinal-lme-lmer.