[R] Fitting a function

[Gabor Grothendieck]

It appears that as one proceeds from right to left that it flattens
out at 0.021 so lets try this where we have added a bit to 0.021 to
avoid log(0)

plot(x, log(0.0211 - y))

and

plot(1/x, log(0.0211 - y))

Except for the first point the latter plot looks linear so lets try:

fm <- nls(y ~ cbind(1, exp(- a / x)), start = c(a = mean(x)), alg = "plinear")
fm
plot(x, y)
lines(x, fitted(fm))

which seems to fit fairly well.


On Fri, May 14, 2010 at 6:36 AM, Dani Valverde <daniel.valverde at uab.cat> wrote:
> Hello,
> It is a very naive question, but here it is. I have this values:
>
> x: 0.5 4 6 8 12
>
> y: 0.021 0.021 0.020 0.018 0.012
>
> I need to fit a function to them. How can I do it with R?
> Thank you so much!
>
> Dani
>
> --
> Daniel Valverde Saubí
>
> Grup de Biologia Molecular de Llevats
> Facultat de Veterinària de la Universitat Autònoma de Barcelona
> Edifici V, Campus UAB
> 08193 Cerdanyola del Vallès- SPAIN
>
> Tlf. +34 93 581 1910
> Fax: +34 93 581 1573
>
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