[R] Preconditions for a variance analysis

[Daniel Tahin]

Thanx for your answer. I don't have the book, but found something on 
the web:
http://www.basic.northwestern.edu/statguidefiles/oneway_anova.html   
and
http://en.wikipedia.org/wiki/Analysis_of_variance#Assumptions

Seems to be the same on both of the sites :-)
Is this, that was meant?

Thanx again,
Daniel




> Dear David
> 
> Yes. There are assumptions that should be verified in an
> analysis of variance. Without checking them, the results are not
> reliable. 
> I'd recommend e.g.
> 
> Robert O. Kuehl, Design of Experiments: Statistical Principles
>   of Research Design and Analysis, Duxbury Press, 2000
> 
> You will find a chapter about assumptions and how to check them
> by residual analysis,
> 
> And also
> 
> W. N. Venables and B. D. Ripley, Modern Applied Statistics 
>   with S, Springer-Verlag, New York, 2002
> 
> in which you find residual analysis and how to obtain it in R.
> 
> Best regards,
> 
> Christoph
> 
> --------------------------------------------------------------
> 
> Credit and Surety PML study: visit our web page www.cs-pml.org
> 
> --------------------------------------------------------------
> Christoph Buser <buser at stat.math.ethz.ch>
> Seminar fuer Statistik, LEO C13
> ETH Zurich	8092 Zurich	 SWITZERLAND
> phone: x-41-44-632-4673		fax: 632-1228
> http://stat.ethz.ch/~buser/
> --------------------------------------------------------------
> 
> 
> Daniel Tahin writes:
>  > Hello everbody,
>  > 
>  > i'm currently using the anova()-test for a small data.frame of 40 
>  > rows and 2 columns. It works well, but is there any preconditions for 
>  > a valid variance analysis, that i should consider?
>  > 
>  > Thank you for your answer,
>  > Daniel
>  > 
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