Thanks, Maarten
______________________________________________
Kieran McCaul MPH PhD
WA Centre for Health & Ageing (M573)
University of Western Australia
Level 6, Ainslie House
48 Murray St
Perth 6000
email: [email protected]
http://myprofile.cos.com/mccaul
_______________________________________________
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Maarten buis
Sent: Friday, 16 November 2007 4:37 PM
To: [email protected]
Subject: RE: st: What is this problem called?
--- Kieran McCaul <[email protected]> wrote:
> For example, if 200 procedures were performed,
> there might be little difference in the average time for the first 50
> procedure compared to the last 50 procedures. I suspect, though,
> that there might be a large difference in the variance of these
times.
> It's the change in variance as more procedures are performed that's
of
> interested.
This seems to be a hetroscedastic model, have a look at chapter 10 of
(McCullagh & Nelder 1989). A similar model that deals with discrete or
ordinal data is sometimes called a hetregeneous choice models, this is
discussed here: http://www.nd.edu/~rwilliam/oglm/index.html
P. McCullagh, John A. Nelder (1989), "Generalized Linear Models",
Second Edition, Chapman & Hall/CRC.
Hope this helps,
Maarten
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
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