[R] multiple error strata in aov
Prof Brian Ripley
ripley at stats.ox.ac.uk
Wed Jun 16 09:02:31 CEST 2004
On Wed, 16 Jun 2004, Murray Logan wrote:
> I am trying to perform a model 3 ANOVA for a 2 factor (say factor A and
> factor B) anova in which factor A is fixed and factor B is random.
> Therefore, the error term for the test of factor A should be the A:B
> interaction term and the error terms for B and A:B should be the model
> residual (within) term. I have tried to work out how to specify such
> error strata using aov, however, I have had little success. Is there a
> way to specify just the interaction (A:B) as an error term using Error()
> within aov or provide a list of error strata.
> Ideally as Error=list(A="A:B",B="Within", A:B="Within")
Error is documented in ?aov, which has a reference. Have you read it?
It does contain the answer to your question. I will not try to explain it
here, and your attempt at specification suggests you do not understand the
meaning of `strata' here. The strata are function of the way the
experiment was designed, not the AOV tables you want which should be a
consequence of the design.
> In addition, I have tried using lme to perform this function, but again
> without much success.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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