Hi group,

I'm trying to do a Tukey test to compare the means of a factor 
("treatment") with three levels in an lme model that also contains the 
factors "site" and "time":

model = response ~ treatment * (site + time)

When I enter this model in csimtest, it takes all but the main factor 
"treatment" as covariables, not as factors (see below).

Is it possible to correctly calculate Tukey contrasts for one factor in a 
lme model with multiple factors using csimtest or another function in R? If 
so, how can I do this?

Many thanks,

René Eschen.


# 
summary(simtest(response~treatment*(site+time),type="Tukey",whichf="treatment"))
#         Simultaneous tests: Tukey contrasts
#Call:
#simtest.formula(formula = response ~ treatment * (site +  time), whichf = 
"treatment", type = "Tukey")
#
#         Tukey contrasts for factor treatment, covariables:  site +time 
+treatment:site + treatment:time
#
#Coefficients:
#                      Estimate t value Std.Err. p raw p Bonf p adj
#treatment3-treatment1   -0.655  -2.004    0.327 0.050  0.149 0.120
#treatment3-treatment2   -0.581  -1.777    0.327 0.081  0.162 0.143
#treatment2-treatment1   -0.074  -0.227    0.327 0.821  0.821 0.821

___
drs. René Eschen
CABI Bioscience Switzerland Centre
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