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st: RE: mean comparison
From
Nick Cox <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
st: RE: mean comparison
Date
Wed, 17 Nov 2010 13:07:56 +0000
What are your grounds for saying that one variable is normally distributed and the other not?
An optimistic take on this question is that the t-test is not as sensitive to non-normality as many appear to believe. If you run a t-test _and_ e.g. Mann-Whitney you may find similar P-values. But the latter is not a test of whether means are different. I don't know what non-parametric tests for comparing means you have in mind.
A pessimistic take is that if the distributions are very different, reducing comparison to a test on means may be an over-simplification, or even quite the wrong question. Getting very different P-values could be consistent with that.
Plotting a graph is usually called for too.
Nick
[email protected]
dk
I have data for two variables for one sample, want to compare means
of them, i can use t test or non-parametric test, but the problem is
that my one variable is normally distributed and other is not, hence
which test I should use,
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