Message-ID: <490388.24771.qm@web32206.mail.mud.yahoo.com>
Date: 2010-01-08T02:42:24Z
From: Moshe Olshansky
Subject: Polynomial equation
In-Reply-To: <1262914361885-1009398.post@n4.nabble.com>
Hi Chris,
You can use lm with poly (look ?lm, ?poly).
If x and y are your arrays of points and you wish to fit a polynom of degree 4, say, enter: model <- lm(y~poly(x,4,raw=TRUE) and then summary(model)
The raw=TRUE causes poly to use 1,x,x^2,x^3,... instead of orthogonal polynomials (which are "better" numerically but may be not what you need).
Regards,
Moshe.
--- On Fri, 8/1/10, chrisli1223 <chrisli at austwaterenv.com.au> wrote:
> From: chrisli1223 <chrisli at austwaterenv.com.au>
> Subject: [R] Polynomial equation
> To: r-help at r-project.org
> Received: Friday, 8 January, 2010, 12:32 PM
>
> Hi all,
>
> I have got a dataset. In Excel, I can fit a polynomial
> trend line
> beautifully. However, the equation that Excel calculates
> appear to be
> incorrect. So I am thinking about using R.
>
> My questions are:
> (1) How do I fit a polynomial trendline to a graph?
> (2) How do I calculate and display the equation for that
> trendline?
>
> Many thanks for your help. Greatly appreciated.
>
> Chris
> --
> View this message in context: http://n4.nabble.com/Polynomial-equation-tp1009398p1009398.html
> Sent from the R help mailing list archive at Nabble.com.
>
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