[R] reference on contr.helmert and typo on its help page.

[David Winsemius]

On Nov 8, 2009, at 11:03 AM, Peng Yu wrote:

> I'm wondering which textbook discussed the various contrast matrices
> mentioned in the help page of 'contr.helmert'. Could somebody let me
> know?
>

My version of "Modern Applied Statistics in S" (aka MASS) deals with  
it in enough detail for a person with background to understand. At one  
point I asked Ripley whether later editions of MASS expanded the  
coverage of that topic but my memory is that he did not reply. Coming  
from a perspective that emphasized regression, I found it rather terse  
(2 pages), so there might be one of the more recently published texts  
that spends more time developing the concepts from basics.

"Statistical Models in S" also covers the topic (5 pages)  in an early  
chapter, again at a level that assumes prior training in ANOVA models.

> BTW, in R version 2.9.1, there is a typo on the help page of
> 'contr.helmert' ('cont.helmert' should be 'contr.helmert').
>
> ______________________________________________
-- 

David Winsemius, MD
Heritage Laboratories
West Hartford, CT