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Re: st: RE: Michaelis-Menten and regression


From   Roger Newson <[email protected]>
To   [email protected]
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
[email protected]

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.
>

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--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
King's College London
5th Floor, Capital House
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Opinions expressed are those of the author, not the institution.

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