When stretch over enough data almost any order will become a pseudo 
straight line ...

By their nature a first order IS a straight line, 2nd U shape, 3rd 
order sine wave etc ...

Try highlighting a SMALLER segment of data by using the beginning and 
ending range markers ...


--- In [email protected], "d_hanegan" <[EMAIL PROTECTED]> wrote:
>
> Fred:
> 
> Thanks for your posts and all of the information concerning the 
> Polynomial Trendlines.  When I run the code, I pretty much just get 
> a straight green line; it does not fit my data.  I thought I had 
> read all of the posts.  Am I missing something? 
> 
> Thanks.
> 
> Dan
> --- In [email protected], "Fred" <ftonetti@> wrote:
> >
> > Be AWARE ... that was a hand picked image ... if you play with 
> > PolyFit you will see that sometimes data fits the extrapolations, 
> > sometimes it doesn't.
> > 
> > The higher the order, the flakier the extrapolations are likely 
to 
> > become ...
> > 
> > So ... Remember what it is ... a generator of an equation in the 
> form 
> > 
> > Y = a + bx + cx^2 + ... + nx^(n-1)
> > 
> > Where the coeeficients were pick to fit the data.
> > 
> > IMHO what PolyFit is, epecially with very high orders is a very 
> good 
> > detrender of IN SAMPLE data, nothing more, nothing less ... That 
> in 
> > and of itself is a useful tool ... Gaussian Elimination can also 
> be 
> > the basis for some other things that are pretty decent when the 
> order 
> > is kept fairly low i.e. 3 or 4 ...
> > 
> > --- In [email protected], "Ara Kaloustian" <ara1@> wrote:
> > >
> > > Polynomial TrendlinesFred,
> > > 
> > > There have been a lot of posting on this subject.  Your one 
> image 
> > however is a very powerful message of its potential.
> > > 
> > > Now I have to go back and review all the post ... hoping to 
find 
> a 
> > good reference to study.
> > > 
> > > Anyone using it succesfully now?
> > > 
> > > Ara
> > >   ----- Original Message ----- 
> > >   From: Fred Tonetti 
> > >   To: [email protected] 
> > >   Sent: Tuesday, October 03, 2006 3:32 PM
> > >   Subject: [amibroker] RE: Polynomial Trendlines
> > > 
> > > 
> > >   Oops .
> > > 
> > >    
> > > 
> > >   Meant to include this visual .
> > > 
> > >    
> > > 
> > >   Green is calculated . White is extrapolated .
> > > 
> > >    
> > > 
> > >    
> > > 
> > > 
> > > 
> > > ----------------------------------------------------------------
-
> ---
> > ----------
> > >   I am using the free version of SPAMfighter for private users.
> > >   It has removed 8588 spam emails to date.
> > >   Paying users do not have this message in their emails.
> > >   Try SPAMfighter for free now!
> > >
> >
>







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