lme() direction

Mike Lawrence <mike <at> thatmike.com> writes:

Would it improve things if "type" were a continuous variable rather
than categorical? I chose words at the extreme ends of a valence
rating scale but I still have the raw valence ratings for each word.

With the interaction, the extreme would be
summary(lme(rt~type*color*word, data=a,random=~1|id))

or, less extreme

summary(lme(rt~type*color+color:word, data=a,random=~1|id))

..
Something like

summary(lme(rt~type*color+color:as.numeric(word), data=a,random=~1|id))

(please replace as.numeric() by the raw valence, the example above it
simply wrong)

could gain you a few degrees of freedom if you are willing to accept the 
linear hypothesis. And as there is something like raw valence, one should
not throw away details about a-priori ordering in favor of a categorical
hypothesis.

Dieter