confirming a formula for use with lmer
Matthew Panichello <panichem <at> nmr.mgh.harvard.edu> writes:
[snip]
I am interested in the effects of variables 'prime','time', and 'mood' on 'reaction_time' while taking into account the random effect 'subjects.' I've read through documentation on lme4 and came up with the following formula for use with lmer: reaction_time ~ (mood*prime*soa) + (1|subject) Prime and soa were repeated measures within subjects, while mood was manipulated between subjects. As I understand it, however, this distinction does not affect how the formula should be written.
[snip] This looks reasonable. If 'prime' and 'soa' vary within individuals, you might want to consider (mood*prime*soa) + (prime*soa|subject): see Schielzeth, Holger, and Wolfgang Forstmeier. 2009. ?Conclusions Beyond Support: Overconfident Estimates in Mixed Models.? Behavioral Ecology 20 (2) (March 1): 416?420. doi:10.1093/beheco/arn145. http://beheco.oxfordjournals.org/content/20/2/416. Followups to r-sig-mixed-models at r-project.org.