[R] type III Sum Sq in ANOVA table - Howto?

Frank E Harrell Jr fharrell at virginia.edu
Fri Mar 7 12:53:55 CET 2003


On Fri, 7 Mar 2003 17:46:11 +1000 
Bill.Venables at cmis.csiro.au wrote:

> Having sounded off on this issue so frequently (and furiously) in the past
> it is perhaps de rigeur for me to say something here...  I'm older and
> calmer now, though.
> 
.... [much wisdom truncated] ...

After Bill Venables' welcome post I'll add :) 

There is one scientific basis for choosing type III contrasts.  If one desires a low-precision contrast (or a low power test) in the presence of major imbalances, type III is for you.
--- 
Frank E Harrell Jr              Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine  http://hesweb1.med.virginia.edu/biostat



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