This question already has an answer here:
- R's lmer cheat sheet 3 answers
I often confuse symbols
* in the
R formulas, particularly when fitting mixed models with
lme4. Can somebody explain clearly the differences between them?
Later edit by @amoeba (Jan 2018): this question had a long and extremely confusing R code. I cut it all out for the benefit of future readers. Please see edit history if interested.