I want to fit a model using the R lme4 lmer function, and I'm not sure how to specify a random effect that is nested within a fixed effect.
I am applying a
Treatment (fixed effect) to a subject, after which s/he is prompted to speak a word that uses exactly one of the 4 mandarin tones (
Tone effect, fixed). Their response time,
RT, is measured as the response variable.
Each tone is expressed 6 times, once via use of each of 6 different, predetermined words (
Word effect, random). There is no overlap of words between tones (i.e. each word uses precisely one of the 4 tones, so there are a total of 24 words used).
Below is the syntax I was thinking of for my model. Is this the right way to specify the described nesting of
Tone? In particular, do I need to specify the association
Tone:Word as the random variable, or should I simply use
Word by itself?
RT ~ 1 + Treatment*Tone + (1+ Treatment*Tone | Tone:Word)