Re: Contrasts

Dear jason
It worked great and had the same results as using "!CONTRAST n1 Nitrogen
-1 0 0 1" in ASReml. Thanks!

Could you also please shed me some light on how to setup contrasts with
interaction terms, say "Variety_Marvellous vs. Variety_Victory in
Nitrogen_0.2_cwt"? I believe that the contrast involves both the Variety
effect and the Variety by Nitrogen interaction.
****this is simple, and only requires you to not fit the main effect of
Nitrogen. SO form the

v1<- V-M - V_V contrast as in the text script and simply fit v1 + Variety
+ v1:Nitrogen + Variety:Nitrogen and then the effects for both interaction
terms should be nested within Variety. This follows from the definition of

A/B = A + A:B

where B is "nested on" A
 

warm regards

Brian Cullis
Research Leader, Biometrics &
Senior Principal Research Scientist
NSW Department of Primary Industries
Wagga Wagga Agricultural Institute

Visiting Professorial Fellow
School of Mathematics and Applied Statistics
Faculty of Informatics
University of Wollongong

Professor,
Faculty of Agriculture, Food & Natural Resources
The University of Sydney

Adjunct Professor
School of Computing and Mathematics
Charles Sturt University

Phone: 61 2 6938 1855
Fax: 61 2 6938 1809
Mobile: 0439 448 591
 
Received on Sat Jul 10 2009 - 07:30:23 EST