Hi,

Anova compare the means of more than two groups, in your case anova test 
H0 hypothisis

H0:  means(control)=mean(tread1)=mean(tread2)=mean(tread3), if there is 
at least one différence,
you can identify the mean difference between groups by using post hoc 
test to testing your B suggestion.

Regrads
ML

Le 29/11/11 11:49, syrvn a écrit :
> Hello,
>
>
> imagine the following experimental design:
>
> Group - Value
>
> control - 5
> control - 6
> control - 5
>
> treated1 - 8
> treated1 - 9
> treated1 - 9
>
> treated2 - 15
> treated2 - 16
> treated2 - 15
>
> treated3 - 25
> treated3 - 30
> treated3 - 28
>
>
> What I like to know is if I apply an ANOVA to this data and choose the
> control group as the reference group (using the relevel function)
> what groups exactly are compared? Are only all treated groups 1, 2, 3 tested
> against the control group or are all possible combinations tested?
>
> What is compared?
>
> A) Testing: control vs treated1; control vs treated2; control vs treated3;
>
> or
>
> B) Testing: control vs treated1; control vs treated2; control vs treated3;
>
>                  treated1 vs treated2; treated1 vs treated3; treated2 vs
> treated3;
>
>
> Cheers
>
>
>
>
>
> --
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> Sent from the R help mailing list archive at Nabble.com.
>
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>


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