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
 

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 11:27
 

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