[R] Question about curve fitting...

[Dan Bolser]

On Wed, 10 Aug 2005, S.O. Nyangoma wrote:

>I see that 
>log(y)=log(k1)+k2*log(x)
>use lm?

Thats a nice solution in this instance, but in general how do I get R to
fit a particular function (formula) and return the parameters?

Cheers,
Dan.

>
>----- Original Message -----
>From: Dan Bolser <dmb at mrc-dunn.cam.ac.uk>
>Date: Wednesday, August 10, 2005 11:41 am
>Subject: [R] Question about curve fitting...
>
>> 
>> Meta:
>> This question is somewhat long and has two parts, I would be very 
>> happyfor someone just to nudge me in the right direction with the 
>> manual /
>> tutorial, as I am somewhat lost...
>> 
>> 
>> 1) How do I fit a curve of the form "y = k1 * x^k2" ?
>> 
>> I want to estimate values of k1 and k2 given the x/y data I have, 
>> and I
>> can't work out how to get R to calculate and return their estimates.
>> 
>> 
>> 2) Given the value of k1 and k2 for population A, how can I test if
>> population B has significantly different values of k1 and k2?
>> 
>> Sorry for the basic question. I think I just need to read up on a few
>> functions.
>> 
>> 
>> I have about 50 xy pairs in total if that makes a difference.
>> 
>> Dan.
>> 
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>