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st: re: ANOVA model


From   David Airey <david.airey@Vanderbilt.Edu>
To   statalist@hsphsun2.harvard.edu
Subject   st: re: ANOVA model
Date   Sat, 28 Sep 2002 12:06:29 -0500

Thanks Ken. That repeated nested ANOVA sounds very similar. I think I was confused because of two situations:

----------------------------------------------------------------------
Animal 1 2 3 4 5
/ \ / \ / \ / \ / \
Location 1 2 1 2 1 2 1 2 1 2
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \
Neuron 01-03 04-06 07-10 11-12 13-15 16-18 19-21 22-24 25-27 28-30
----------------------------------------------------------------------

and

-----------------------------------------------------------------
Animal 1 2 3 4 5
/ \ / \ / \ / \ / \
Neuron 1 2 3 4 5 6 7 8 9 10
/// \\\ /// \\\ /// \\\ /// \\\ /// \\\
Treatment 123 123 123 123 123 123 123 123 123 123
-----------------------------------------------------------------

In the second model each neuron is exposed to each treatment, such that there are 3 measures per individual neuron. In the first model, each neuron is measured once. So in the second model, I had thought it was like a nested repeated measures ANOVA, analogous to the book example with the repeated factor being treatment and neuron nested in animal. And I thought the first example was somehow different. I see that location is the repeated "treatment" on every animal, but I thought neuron should be nested in location not animal. Am I wrong or does what happens underneath make this point irrelevant? Should neuron be nested in animal in both models? Maybe my diagrams should be represented differently.

-Dave

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