N+M gives only the main effects, N:M gives only the interaction, and G*M gives
the main effects and the interaction.
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org] On Behalf Of Birgit Lemcke
> Sent: Friday, May 16, 2008 11:27 AM
> To: R Hilfe
> Subject: [R] glm model syntax
>
>
> Hello R users!
>
> What is the difference between
>
> glm(A~N+M)
> glm(A~N:M)
> glm(A~N*M)
>
> Thanks in advance.
>
> Birgit
>
> Birgit Lemcke
> Institut f?r Systematische Botanik
> Zollikerstrasse 107
> CH-8008 Z?rich
> Switzerland
> Ph: +41 (0)44 634 8351
> birgit.lemcke at systbot.uzh.ch
>
> 175 Jahre UZH
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> Informationen http://www.175jahre.uzh.ch/naturwissenschaft
>
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