[R] Post Hoc Groupings

Jarrett Byrnes jebyrnes at ucdavis.edu
Thu Oct 27 02:35:12 CEST 2005

Indeed, the following works as well
On Oct 26, 2005, at 5:23 PM, P Ehlers wrote:

> fm1 <- aov(breaks ~ wool*tension, data = warpbreaks)
> TukeyHSD(fm1, c("wool","tension", "wool:tension"))

However, when working with my own dataset,  I get the following errors. 
  I have some inkling this may be due to a slightly unbalanced sample 
size, but am uncertain of this.

 > rich.aov <- aov(X.open ~ Dock*Slip, data=dock_2004_data)
 > TukeyHSD(rich.aov, c("Dock", "Slip"))

Error in rep.int(n, length(means)) : unimplemented type 'NULL' in 'rep'
In addition: Warning messages:
1: non-factors ignored: Slip in: replications(paste("~", xx), data = mf)
2: non-factors ignored: Dock, Slip in: replications(paste("~", xx), 
data = mf)

I am pleased to know that these errors are not quite the

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