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re: st: Re: Anova and contrasts
Dave,
Thanks for that I will look at smileplot.
Yes, I was also looking for a simpler way of inputting the matrix which
would be 8*54 in this case. So far creating the matrix in either Excel or
Notetab and then trying to import it have nor been successful.
Janet
From: David Airey <[email protected]>
Reply-To: [email protected]
To: [email protected]
Subject: re: st: Re: Anova and contrasts
Date: Mon, 11 Dec 2006 10:02:56 -0600
I am interested in looking at the system*material interactions in more
detail. I have carried out "all possible" comparisons using:
.. test _coef[system[1]*material[1]]=_coef[system[1]*material[2]]
etc.
It occurs to me that I should setup a contrast matrix test this using the
mtestand allow for multiple testing. The problem is that the design
matrix has 54 columns. Do I need to set up this matrix for the 4
comparisons that I need or is there a more efficient (or simpler)
approach.
Many thanks.
When you get a significant interaction, there are two ways to follow it
up. One is with simple main effects, the other is with interaction
contrasts. Seems you are doing the latter, and you see the prospect of
typing in a big matrix annoying? Is that the question? Maybe there is a
quicker way to type that in? I'd be interested in the answer too. You
might also try the look at simple main effects with the command sme
(findit sme). An example is at UCLA:
http://www.ats.ucla.edu/stat/Stata/faq/sme.htm
Another possibility, if you have done all comparisons as you said, is to
pass those statistics or p values to a multiple test correction command
like smileplot (findit smileplot).
-Dave
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