It might be a simple question but I cannot seem to see examples anywhere on how to fit more than two levels for a multilevel (or hierarchical) model using rstanarm. I am learning how to do Bayesian analyses. and I have data I would like to run a Bayesian analysis on and my data has four levels. I saw examples that could fit two levels like this below:
TwoLevelModel <- stan_lmer(y ~ x + (1 + x | variable), data = dat)
If I want to fit four levels, how would I write a model using rstanarm? My four levels are: Quadrat nested into Transect nested into Site nested into Cape. Thank you!