Ah, Ron�n's interpretation of your question makes a lot more sense.
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting adress:
Buitenveldertselaan 3 (Metropolitan), room Z214
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of Ron�n Conroy
Sent: dinsdag 11 april 2006 12:24
To: [email protected]
Subject: Re: st: finding a peak in an asymmetric curve
On 11 Aib 2006, at 09:17, Yoshiro Nagao wrote:
> Are there any statistical method
> to find the value of x for the peak,
> and show its "significance"?
Check Stata's routines for analysis of pharmacokinetic data (pretend
your nutrient values are time and you'll fool it).
. pkexamine nutrient longevity
Warning: the point (0, 0) is not in your data. It will be added.
Maximum concentration =
362.5851
Time of maximum concentration
= .02
Time of last observation (Tmax) = .
049458
Elimination rate =
15.2374
Half life =
0.0455
Area under the curve
-----------------------------------------------------------------------
| AUC [0, inf.) | AUC [0, inf.) | AUC [0,
inf.)
AUC [0, Tmax] | Linear of log conc. | Linear fit |
Exponential fit
----------------+---------------------+---------------
+----------------
14.64 | 31.413 | 22.994 | 31.413
-----------------------------------------------------------------------
Fit based on last 3 points.
You may also look at -fracpoly- which fits fractional polynomials to
your data.
I'm not sure what the "significance" of a peak is, and I notice that
you have rather shyly surrounded it with quotes. What exactly do you
want to find out about the peak.
=========
Ron�n Conroy
[email protected]
+353 (0) 1 402 2431
+353 (0) 87 799 97 95
www.flickr.com/photos/ronanconroy
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