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st: Gompertz equation
From
Michael Begg <[email protected]>
To
[email protected]
Subject
st: Gompertz equation
Date
Wed, 23 Mar 2011 11:24:20 +1100
Hi all,
I am trying to estimate the equation y = b1*exp(b2*exp(b3*x)) using the
following:
nl (y = b1*exp(b2*exp(b3*x)))
Stata takes b3 as a constant and b2 is omitted.
Why is this happening?
If I use the inbuilt gompertz function form y = b1*exp(-exp*(b2*(b3 - x)))
using
nl gom3: y x
it works fine.
Thanks for your help
Cheers
Michael
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