ANOVA Output

That's a great point Tyler.  It raises the question of what IS a good reference for statistics that treats them the way R does.  There has been some discussion of that already, but one book that hasn't been mentioned is that of John Fox, the author of the car package.

Fox, John.  1997.  Applied regression analysis, linear models, and related methods.  Sage Publications.

http://books.google.com/books?id=pr2mKvAxXeYC&printsec=frontcover&lr=

Although mainly aimed at the social sciences, I found this to be pretty readable, and much more detailed than Crawley's books (admittedly aimed at a higher level).  And as for R code, Fox also has "An R and S-Plus Companion to Applied Regression". http://books.google.com/books?id=xWS8kgRjGcAC&printsec=frontcover&lr=

 If you want to get a detailed understanding of Anova and regression the way R sees them, I think this pair of books is nearly as good as it gets.

Matt

-----Original Message-----
From: r-sig-ecology-bounces at r-project.org [mailto:r-sig-ecology-bounces at r-project.org] On Behalf Of tyler
Sent: Thursday, November 13, 2008 8:52 AM
To: r-sig-ecology at r-project.org
Subject: Re: [R-sig-eco] ANOVA Output

Apologies if I'm beating a dead horse here, but this is exactly the
problem I raised in the thread on classical statistics in R. If Katrina
is using a textbook like Sokal and Rohlf, it is indeed completely
unexpected to find that changing the order of explanatory variables in
an anova will produce different results. Thierry points out that this is
because R produces Type I SS by default. Unfortunately, nowhere in S&R
is this distinction explained, so for this problem a book widely
regarded as a comprehensive reference for biologists provides absolutely
no help.

These questions come up all the time on the r-help list, and I think
it's a sign of a real disconnect between the presentation of classical
statistics in many undergrad programs and the way the tests are actually
implemented in R.

Anyways, that's a bigger issue. It may be helpful to know that the 'car'
package includes a function Anova (not to be confused with the anova
function) that allows you to calculate type II or type III sums of
squares.

Cheers,

Tyler

"ONKELINX, Thierry" <Thierry.ONKELINX at inbo.be>
writes:

ANOVA Output

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