Hello,
I am analyzing some data that has violated assumptions of ANOVA and am
using the WRS2 package in R. I am comparing three groups, Dx,
(schizophrenia, schizoaffective and control) on various variables, one of
which is premorbid IQ (preIQ).
preIQdataSDx #trimmed means > tapply(preIQdataSPreIQ, preIQdataSDx,
mean,
tr=.2, na.rm=TRUE) Schizophrenia Schizoaffective Control 89.29412 95.83333
95.54545
>
The post hoc test shows that the schizophrenia and controls group differ
significantly which makes sense when you look at their trimmed means;
however, what does not make sense is that the control and schizoaffective
disorder groups differ significantly from each other (their means are
almost identical). Additionally, if the schizophrenia and control group
differ significantly, shouldn't the schizophrenia group also differ
significantly from the control group too, as the control group and
schizoaffective disorder groups have very similar means. I am wondering if
the lincon post hoc test is flawed in some way or if I am not setting
something up correctly in R. Any help is greatly appreciated. Thank you.
Best,
Leah Hartman
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