[R] broken example: lme() + multcomp() Tukey on repeated measures design

[David Winsemius]

On Apr 21, 2009, at 10:12 AM, William Simpson wrote:

> I am trying to do Tukey HSD comparisons on a repeated measures expt.
> I found the following example on r-help and quoted approvingly  
> elsewhere.
> It is broken. Can anyone please tell me how to get it to work?
>
> I am using R 2.4.1.

How many years have you had that version without updating?
>
>
>> require(MASS) ## for oats data set
>> require(nlme) ## for lme()
>> require(multcomp) ## for multiple comparison stuff
>> Aov.mod <- aov(Y ~ N + V + Error(B/V), data = oats)
>> Lme.mod <- lme(Y ~ N + V, random = ~1 | B/V, data = oats)
>> summary(Aov.mod)
>> anova(Lme.mod)
>> summary(Lme.mod)
>> summary(glht(Lme.mod, linfct=mcp(V="Tukey")))
> Error in eval(expr, envir, enclos) : object "Y" not found
> Error in factor_contrasts(model) : no 'model.matrix' method for  
> 'model' found!

It is not broken when run in version 2.8.1.


David Winsemius, MD
Heritage Laboratories
West Hartford, CT