Hi list,
I was wondering how I should go about fitting a sigmoid curve to a dataset.
More specifically how I estimate parameters a and b in the following equation:
1 / 1+exp(-(x-a)*b)
with b the steepness of the sigmoid curve and a the shift of the center of the
sigmoid curve relative to the center of your dataframe. The fit is in function
of x, the location within the input vector and y, an ecological value.
So I would like to estimate parameters a and b and a goodness of fit/ F-value
of some kind.
Any suggestions?
Kind regards,
Koen
--
Checked by AVG Free Edition.
11:27
[[alternative HTML version deleted]]
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
