[R-sig-ME] random as fixed effect

Ben Bolker bbolker at gmail.com
Thu Oct 11 14:07:33 CEST 2012

joana martelo <jmmartelo at ...> writes:

> I’m modeling fish activity data with a gaussian distribution for scores
> obtained from Principal Component Analysis. My explanatory variables are
> group size, fish length, temperature and year. Because year has only two
> levels I know I can’t use it as a random effect. However, do you think that
> considering year a fixed effect will inflate the effect of the other
> explanatory variables? 

  No.  On the basis of what you've told us, using year as a fixed
effect seems perfectly sensible.  You might want to check whether
there are important interactions between year and the other explanatory
variables ...

  (Your title seems a bit odd.)

  Ben Bolker

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