[R] ANCOVA with defined error terms

hpdutra hpdutra at yahoo.com
Sat Aug 22 17:36:35 CEST 2009

Thank you Richard, this works. But, the model you suggested me lacks some
between subjects  interactions, namely:
 According to Sokal and Rohlf I need to report those as well. 
Also, any ideas why the sum of squares on my model are different from yours

data = track))))
reports veg:fruit with a sum squares of 80.5

while yours 
summary <- (ricsmodel<-aov(mice ~ coon + block*veget*fruit*time -
block:veget:fruit:time+ Error(block/plot), data = track))
gives me a veget:fruit sum of squares of 253.2
the residuals degrees of freedom also differ my model gives 4 DF for the
between subjects while yourr does not report one for the between subjects. 
I know I'm asking too much, but I'm just trying to understand.

Richard M. Heiberger wrote:
> Yes, I meant summary().  anova() isn't defined for aovlist objects and 
> summary() is.
>> Warning message:
>> In aov(kotz.mice ~ kotz.coon + block * veget * fruit * time -
>> block:veget:fruit:time +  :
>>   Error() model is singular
> You will need to investigate the singular Error() model.  You might want
> to use the simpler Error model
> Error(block)
> My guess is the plot term is redundant.
> What are kotz.mice?  That variable isn't in the model you showed.
> For more detailed help you will need to
> "provide commented, minimal, self-contained, reproducible code."
> Rich
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

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