SPSS N-way AN?OVA -> R ? (was [R] Unbalanced ANOVA in R?)

[ripley@stats.ox.ac.uk]

On Fri, 8 Mar 2002, Fredrik Karlsson wrote:

> Thank you Professor Ripley for the quick and informative response.
>
> Being unable to choose a different textbook (even though I must admit
> that this SPSS obsession is starting to annoy me).

You could read a textbook on S/R which would explain what aov does.  As I
understand it John Fox's car package is designed (amongst other things) to
make R easier for diehard SPSS users, so you ought to find that useful.

> I solved the problem though.
>
> I changed the subject for this post in order to change the topic into
> a more general one:
>
> What does aov() do and what does it NOT do?
> Prof. Ripley mentioned that you should use the lme() function  for
> multistrata anova, so that's one. What else? (Realising that this is a
> question with an open set of answers).

No, for *unbalanced* multistrata anova (and that's the second time you
have quoted me out of context: please be more careful!).  For balanced
desigms, aov()  is the preferred tool.  It's also general for unbalanced
fixed-effects models, but for some lm will be able to interpret.

> My impression is that what I am suppose do do in SPSS under some heading
> n-way anova, ancova,  one-way glm or whatever is handled in S/R by aov()
>
> Does this mean you can use aov() to compare two groups with different
> ns?

You can, but that's the job of t.test.

> Many open questions, I know, but the SPSS -> R translation is troubling
> for me.

It's troubling for us.  SPSS is often grossly misleading in its
terminology.

-- 
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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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