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From: "John D'Errico" <woodchips@rochester.rr.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Non-polynomial Curve Fit problem
Date: Thu, 16 Apr 2009 21:09:01 +0000 (UTC)
Organization: John D'Errico (1-3LEW5R)
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"lan " <amoyjiajia@hotmail.com> wrote in message <gs8471$b8v$1@fred.mathworks.com>...
> John:
> 
> What is the idea of your simple model. I can not follow it. Thanks,

A polynomial fit for this data is simply fatuous.
I'm sorry, but it would be ridiculous in the
extreme. Just to throw random data into a
computer and expecting anything sensible to
come out, with no further input from the 
scientist, analyst, or other knowledgeable
person?

You have no model for the curve, nor have you
expressed any indication that there should be a
model, mechanistic or not, for this data. It is
apparently not much more than a random walk.
The best predictor for such a random process is
probably just the mean of the data. Certainly so
if you have no other information to provide.

john