[R] Question about lme syntax

[angelo.arcadi at virgilio.it]

Dear list,
I need an help to understand the syntax of lme to fit my model according to the analysis I want to perform.

My dependent variable resulted from a perceptual experiment in which responses of participants were measured twice for each provided stimulus. My goal is to verify whether the responses depend on two properties of the participants that I know to be related to each other (height and weight, so they need to be considered together as an interaction). More importantly, I need to understand how this relationship modulates according to the type of stimulus participants were presented to.

Based on my understanding of lme syntax, the formula I have to use should be the following (because I am only interested in the interaction factor of Weight and Height)

lme_dv <- lme(dv ~ Weight:Height:Stimulus_Type, data = scrd, random = ~ 1 | Subject)

Am I correct?


Thank you in advance

Best regards

Angelo



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