Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: RE: Michaelis-Menten and regression


From   Roger Newson <roger.newson@kcl.ac.uk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Michaelis-Menten and regression
Date   Mon, 27 Sep 2004 22:26:20 +0100

Nick's guess re Nelder recommending a gamma family is probably right. I recall that he recommended it (together with an inverse link) in a conversation I remember from my days at Rothamsted about Michaelis-Menten functions.

Roger

At 15:23 22/09/2004, Nick Cox wrote (in reply to Simon Moore):


In Stata terms

. gen rec_x = 1 / x
. glm y rec_x, link(power -1)

Of course, all this is just algebra with the
deterministic curve and says
nothing about error structure.

Nelder I guess recommends using a gamma
family.

Nick
n.j.cox@durham.ac.uk

Simon Moore

> I have a reasonably simple hypothesis that the form of relationship
> between the independent variable (x) and the dependent variable (y)
> follows the Michaelis-Menten rational function, f(x) = ax/(1+bx).  I
> want to have this in a regression model with the cluster() option: reg
> y f(x) V, cluster().  But I can't see a way of achieving this and
> having reg solve for a and b.  I thought maybe a power expansion of
> f(x) might work, but this does not seem appropriate.
>

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/

--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
King's College London
5th Floor, Capital House
42 Weston Street
London SE1 3QD
United Kingdom

Tel: 020 7848 6648 International +44 20 7848 6648
Fax: 020 7848 6620 International +44 20 7848 6620
  or 020 7848 6605 International +44 20 7848 6605
Email: roger.newson@kcl.ac.uk
Website: http://www.kcl-phs.org.uk/rogernewson

Opinions expressed are those of the author, not the institution.

*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index