Displaying 2 results from an estimated 2 matches for "expfun".
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expfn
2007 Jul 24
1
Fwd: Re: Fitting exponential curve to data points
...out <- nls(Count~b0+b1*Year+b2*Year^2,data=dat, #polynomial
> start=list(b0=0,b1=1,b2=1))
> lines(dat[,1],fitted(out),col=3)
>
> ## Optim
> f <- function(.pars,.dat,.fun) sum((.dat[,2]-.fun(.pars,.dat[,1]))^2)
> fitFun <- function(b,x) cbind(1,x,x^2)%*%b
> expFun <- function(b,x) b[1]*exp(b[2]*x)
>
> plot(dat)
> out <- optim(c(0,1,1),f,.dat=dat,.fun=fitFun)
> lines(dat[,1],fitFun(out$par,dat[,1]),col=2)
> out <- optim(c(1,1),f,.dat=dat,.fun=expFun)
> lines(dat[,1],expFun(out$par,dat[,1]),col=3)
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2007 Jul 24
2
Fitting exponential curve to data points
Hi folks,
I've looked through the list archives and online resources, but I
haven't really found an answer to this -- it's pretty basic, but I'm
(very much) not a statistician, and I just want to check that my
solution is statistically sound.
Basically, I have a data file containing two columns of data, call it data.tsv:
year count
1999 3
2000 5
2001 9
2002 30
2003 62
2004 154