Goal: comparing pitch (Hz) on three types of words
Dependent variable: Hz
Fixed predictor variable: word-type, points (measurements taken from five points on each token, to capture Hz change within a token), gender (females have higher Hz)
Random variable: repetitions, which are nested within items, which are nested within speakers. Each of 15 speaker produces 5 repetitions of 5 items of the same word-type.
My question is, how do I capture the nested nature of my three random variables, with mixed effect model using R? Naively I've tried
which obviously doesn't seem to work.
My full model, run with lme4 package, should like this:
lmer(hz ~ word_type + point + gender + (????), data=dataX)
The problem is that I am not sure I how should write my random variables (repetitions, items, and speakers).