[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
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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