[R] Fitting a curve to to an oscillating scatter . .

reza shahidzadeh mahani mahani at students.uiuc.edu
Sun Aug 13 21:38:44 CEST 2000

```You can  get the lower frequency component nonparametrically by
increasing the bandwidth (in kernel smoothing with ksmooth in S) or
increasing penalty coefficient (in spline smoothing with smooth.spline in
S).
I don't know the corresponding function in R unfrotunately.

method) On Sun, 13 Aug 2000, Prof Brian D Ripley wrote:

> On Sun, 13 Aug 2000, Phil Rhoades wrote:
>
> > I have just got going with R and think it is really nice however, as far as
> > I can see, it can't do what I got it for:
>
> Sure it can.  It is a fully fledging computing language.
>
> > I have some output from a computer simulation of mutating genes represented
> > by a biological statistic - so the graph looks roughly like the top of:
> >
> > 	x = y^2
> >
> > - with oscillations around the general curve.
> >
> > If I use scatter.smooth() I get a nice curve representing the oscillations
> > but what the curve I want to fit is the more basic curve ie the top arm of
> > the x = y^2.
> >
> > Any suggestions?
>
> plot(x, y)
> fit <- lm(y ~ I(x^0.5)) # or y ~ sqrt(x)
> lines(predict(fit), sort(x))
>
> if indeed the response is y to stimulus x.
>
>
> --
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272860 (secr)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>
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