Fitting a sigmoid curve in R #6
Description
Regarding your post "Fitting a sigmoid curve in R" from Jul 8, 2012, I am a newbie to sigmoid curves and am interested to utilize them in network planning in the retail industry.
Specifically, in the fitmodel equation, can you please help me understand where you derived the a=1,b=.5, and c=25 values?
fitmodel <- nls(y~a/(1 + exp(-b * (x-c))), start=list(a=1,b=.5,c=25))
Thank you for your time and consideration. I look forward to your reply.