testing the null hypothesis of no interaction is not the same as a
test of equivalence for the two differences. There is a literature on
tests of equivalence. First you must develop a definition of
equivalence, for example the difference is in the interval (-a,a).
Then, for example, you test the null hypothesis that the difference
is in [a,inf) or (-inf,-a] (a TOST, or two one sided tests). One
simple procedure: check to see if the 90% CI for the difference
(difference of the differences or the interaction effect) is contained
in the interval (-a,a).
albyn
Quoting Greg Snow <greg.s...@imail.org>:
Does it make sense for you to combine the 2 data sets and do a 2-way
anova with treatment vs. control as one factor and experiment number
as the other factor? Then you could test the interaction and
treatment number factor to see if they make a difference.
--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.s...@imail.org
801.408.8111
-----Original Message-----
From: r-help-boun...@r-project.org [mailto:r-help-bounces@r-
project.org] On Behalf Of syrvn
Sent: Saturday, February 12, 2011 7:30 AM
To: r-help@r-project.org
Subject: [R] Test for equivalence
Hi!
is there a way in R to check whether the outcome of two different
experiments is statistically distinguishable or indistinguishable? More
preciously, I used the wilcoxon test to determine the differences
between
controls and treated subjects for two different experiments. Now I
would
like to check whether the two lists of analytes obtained are
statistically
distinguishable or indistinguishable
I tried to use a equivalence test from the 'equivalence' package in R
but it
seems that this test is not applicable to my problem. The test in the
'equivalence' package just determines similarity between two conditions
but
I need to compare the outcome of two different experiments.
My experiments are constructed as follows:
Exp1:
8 control samples
8 treated samples
-> determine significantly changes (List A)
Exp2:
8 control samples
8 treated samples
-> determine significantly changes (List B)
Now i would like to check whether List A and List B are distinguishable
or
indistinguishable.
Any advice is very much appreciated!
Best,
beginner
--
View this message in context: http://r.789695.n4.nabble.com/Test-for-
equivalence-tp3302739p3302739.html
Sent from the R help mailing list archive at Nabble.com.
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______________________________________________
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