Message-ID: <CALzuZRS3MAAMTE_jweerSE+o-pUkqOk=AVr-jmpmryjCenCc-w@mail.gmail.com>
Date: 2012-05-30T20:44:01Z
From: Juliet Hannah
Subject: statistical basis for using mixed model in a situation
All,
Consider a simple two-group design in which one wants to test if the
means of these two groups are different. Assume a simple
t-test (un-paired) is sufficient. Let's say there are 10 samples in
Group A and 10 in group B.
Now, let's say each sample was measured in triplicate so that Group A
has 30 arising from 10 measured in triplicate.
Here is my question:
We could average the triplicates and proceed with the t-test.
But I have also observed people fitting a mixed model with a random
intercept for the triplicates.
What is the statistical basis for selecting one approach over the other?
Off the top of my head, this seems a little different from examples
such as students nested within classes and so on, but
I am unable to properly characterize it statistically.
Thanks,
Juliet