Hi,

Sorry to bother you again.

I would like to estimate the effect of several categorical factors (two
between subjects and one within subjects) on two continuous dependent
variables that probably covary, with subjects as a  random effect. *I want
to control for the covariance between those two DVs when estimating the
effects of the categorical predictors** on those two DVs*. The thing is, i
know the predictors have an effect on DV1, and i know DV2 covaries with
DV1, so it would be "cheating" to simply estimate the effect of the
predictors on DV2 because those effects could be indirect (via DV1), right ?

I see two solutions :

*One solution would be a mixed model MANOVA (if that even exists)*. But i
don't know how to run a mixed model MANOVA, i tried to do it with
Statistica but couldn't find the right module (I know how to declare two
DVs and run a GLM, but *I don't know if the covariance between my two DVs
is automatically controlled for*). Same thing with R. I tried to ask a
question on Statistica's forum with no answer, tried looking around in the
manuals with no improvement.

*A backup solution would be a multiple regression* (regressing DV2 against
DV1 with the categorical predictors). But i am not sure how to implement a
mixed model, which function i should use and besides, it would be *much
less convenient because one of my categorical predictors has three
levels*(so i would have to split it and make it two predictors,
right?).

Thank you for any help at all !

Cheers,

L.

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