Kate,
Nick suggests we don't have enough information to properly answer your
questiion.
I would like to add that specifically, we need to know:
a) but what sort of model for your data you are assuming
b) what paarameters in the model you are trying to estimate. I'll take a
guess:
a) y_ij = mu + a_i + e_ij = j-th measurement on i-th animal
mu is mean creatinine level for a population of animals undergoing (this)
experiment
mu + a_i is mean creatinine level specific to the i-th animal
a_i ~ N(0,siga^2)
e_ij is random variation of measured creatinine level about the mean for the
i-th animal
e_ij ~ N(0, sige^2)
b) you wish to estimate mu and siga
Is this correct? - If not - please give your interpretation of what a) and
b) are.
Al Feiveson
-----Original Message-----
From: Nick Cox [mailto:[email protected]]
Sent: Thursday, January 02, 2003 8:29 AM
To: [email protected]
Subject: st: RE: mean and median with multiple measures
Kate
> I have about 200 measures of creatinine but they are
> from only 25 animals. How do I calculate the mean and
> the median creatinine values in Stata?
Several answers already; but if they don't
provide an answer I think you will need
to tell us more about your data structure.
What variables and what observations do
you have?
Nick
[email protected]
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