Re: [R] fitting a curve to data points

2008-10-07 Thread Dieter Menne
gmail.com> writes: > > Hello all. This is likely to be a silly question, but I have a set of > data points and I want to fit a curve to it, like this: > http://www.igc.usp.br/pessoais/guano/temp/curve.png While you could use a loess-curve, interpreting the rising branch a the end is probably c

Re: [R] fitting a curve to data points

2008-10-06 Thread Rolf Turner
On 7/10/2008, at 2:53 PM, Carlos Guâno Grohmann wrote: Hello all. This is likely to be a silly question, but I have a set of data points and I want to fit a curve to it, like this: http://www.igc.usp.br/pessoais/guano/temp/curve.png. which function should I use? Have a look at smooth.spline(

[R] fitting a curve to data points

2008-10-06 Thread Carlos "Guâno" Grohmann
Hello all. This is likely to be a silly question, but I have a set of data points and I want to fit a curve to it, like this: http://www.igc.usp.br/pessoais/guano/temp/curve.png. which function should I use? many thanks Carlos -- +---+

Re: [R] Fitting a curve to data

2008-07-03 Thread Greg Snow
D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Shirin Safa > Sent: Tuesday, July 01, 2008 2:28 PM > To: stephen sefick > Cc: r-help@r-project.org

Re: [R] Fitting a curve to data

2008-07-02 Thread Vikas Rawal
> There is an integrate.xy in sfsmic. Limitations discussed there. Also see trap.rule in Hmisc Vikas __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-gu

Re: [R] Fitting a curve to data

2008-07-01 Thread Shirin Safa
no this is not what I want. I was using "loess" function or smooth.spline. but For loess I don't know how would I be able to get the integral. On 7/1/08, stephen sefick <[EMAIL PROTECTED]> wrote: > > ?lm > lm(x[,1]~x[,2]) > > On Tue, Jul 1, 2008 at 2:28 PM, Shirin Safa <[EMAIL PROTECTED]> wrote:

Re: [R] Fitting a curve to data

2008-07-01 Thread Carl Witthoft
And, oddly enough :-), integrate.xy does pretty much exactly what I suggested. Thanks for providing that reference I would be interested in seeing how the original poster's data works out using integrate.xy as opposed to simply calculating x*y By the way, since the original data were 'perc

Re: [R] Fitting a curve to data

2008-07-01 Thread Gabor Grothendieck
There is an integrate.xy in sfsmic. Limitations discussed there. On Tue, Jul 1, 2008 at 6:27 PM, stephen sefick <[EMAIL PROTECTED]> wrote: > I would like to know the answer to this question now that I know what we are > getting at. integrate() looks like it is the right thing, but it has to use

Re: [R] Fitting a curve to data

2008-07-01 Thread stephen sefick
I would like to know the answer to this question now that I know what we are getting at. integrate() looks like it is the right thing, but it has to use a function- I would like to know how to just integrate the area under a curve with just an input of x and y coordinates. Stephen On Tue, Jul 1

Re: [R] Fitting a curve to data

2008-07-01 Thread Carl Witthoft
I think the previous answer (to use lm() ) is not necessarily the best option. Since what you want is the definite integral (area under the curve), you can just use one of the existing definite integration tools (sorry, I don't recall the names because I don't use them). If you want to get a

Re: [R] Fitting a curve to data

2008-07-01 Thread stephen sefick
does loess return the values that it produces- take that and then integrate under the curve. On Tue, Jul 1, 2008 at 4:28 PM, Shirin Safa <[EMAIL PROTECTED]> wrote: > no this is not what I want. > I was using "loess" function or smooth.spline. > but For loess I don't know how would I be able to ge

Re: [R] Fitting a curve to data

2008-07-01 Thread stephen sefick
?lm lm(x[,1]~x[,2]) On Tue, Jul 1, 2008 at 2:28 PM, Shirin Safa <[EMAIL PROTECTED]> wrote: > Hi > > I have a set of data like this: > >*Time of Day* *Pct of Daily Volume* 9:45 7.50% 10 6.25% 10:15 4.45% > 10:30 4.80% 10:45 4.45% 11:00 4.20% 11:15 2.50% 11:30 2.30% 11:45 2.25% > 12:00 2.45% 12

[R] Fitting a curve to data

2008-07-01 Thread Shirin Safa
Hi I have a set of data like this: *Time of Day* *Pct of Daily Volume* 9:45 7.50% 10 6.25% 10:15 4.45% 10:30 4.80% 10:45 4.45% 11:00 4.20% 11:15 2.50% 11:30 2.30% 11:45 2.25% 12:00 2.45% 12:15 2.60% 12:30 2.00% 12:45 2.05% 13:00 2.40% 13:15 1.90% 13:30 3.10% 13:45 2.90% 14:00 2.80% 14:15 2.50