On Nov 11, 2010, at 4:16 AM, Ravi Kulkarni wrote:
Hello Forum,
I have data for two groups of subjects for a ratio variable (cortisol
level) assessed three times during the day (at 0600, 0900 and 2100
hours).
So I have three means for each group. I have been asked to do a "slope
analysis" to compare the two groups.
According to my understanding, this means that I regress the three
means
on the time for each group and compare the slopes using a t-test
(there is a
post on this: Etienne Toffin etoffin at ulb.ac.be
Tue Jan 27 20:08:36 CET 2009).
My question: (if what I said is correct) it seems strange to me
that we
calculate a regression line with just three data points - is this
really
what is meant by a "slope analysis"?
Doubtful. What was probably meant was to do a regression with an
interaction model based on the original data. Sounds like either you
or your supervisor need some consulting resources.
--
David.
Any help most appreciated...
Ravi
--
David Winsemius, MD
West Hartford, CT
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