HDoran at air.org
Wed Sep 13 20:41:41 CEST 2017
Perhaps a bit OT, but what *is* an interaction between a fixed and random factor? The fixed effects are estimates, BLUPs are not estimates really.
I can't quite consider what the estimand is in this instance
From: R-sig-mixed-models [mailto:r-sig-mixed-models-bounces at r-project.org] On Behalf Of Ben Bolker
Sent: Wednesday, September 13, 2017 2:34 PM
To: r-sig-mixed-models at r-project.org
Subject: Re: [R-sig-ME] Query
I'm going to say something here to get the conversation started, but this information comes with a giant caveat. I hope that someone with more knowledge of experimental designs comes forward ...
in general an interaction between a random factor r and a fixed factor f is either
(assuming a positive, compound-symmetric variance-covariance matrix) or
(assuming an unstructured variance-covariance matrix). The latter is likely to be very expensive if f has more than a few levels.
Interaction between two random factors would be (1|r1:r2) (you would have (1|r1) and (1|r2) in the model as well).
On 17-09-13 02:12 PM, EZEQUIEL ROSSI wrote:
> I am working with a Federer's augmented block design in lmer function
> and I need indicate interaction between ramdom and fixed factors and
> between two ramdom factors . Can you say me how I should make this?
> Thank you very much,
> Best regards,
> Ezequiel Rossi
> [[alternative HTML version deleted]]
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