Stats/Maths filter: How do I solve a sigmoidal?
May 24, 2009 8:53 PM Subscribe
I am trying to fit my data onto a sigmoidal function. The fit won't be perfect, but I am stuck with it for now.
To help with this, I have been (very generously) given a spreadsheet that creates a sigmoidal curve if the values a, b, x0 and x are known. How do I get these values?
posted by doctor.dan to science & nature (8 answers total) 1 user marked this as a favorite
The excel spreadsheet that I have implements a three-parameter sigmoidal function
All I know so far is that x
is my cutoff (70th percentile) which is solved using the restructured equation
I've scoured the interwebs for help on this, but I can't for the life of me figure out how to solve for a
, and what x0
is meant to be. All online resources I have found so far are either really basic (what is a sigmoidal function), or too advanced (how to fit real-time PCR to a sigmoidal function).
Any help would be great.