expyfun.analyze.fit_sigmoid#

expyfun.analyze.fit_sigmoid(x, y, p0=None, fixed=())[source]#

Fit a sigmoid to summary data

Given a set of average values y (e.g., response probabilities) as a function of a variable x (e.g., presented target level), this will estimate the underlying sigmoidal response. Note that the fitting function can be sensitive to the shape of the data, so always inspect your results.

Parameters:

xarray-like: x-values along the sigmoid.
yarray-like: y-values at each location in the sigmoid.
p0array-like | None: Initial guesses for the fit. Can be None to estimate all parameters, or members of the array can be None to have these automatically estimated.
fixedlist of str: Which parameters should be fixed.

Returns:

lower, upper, midpt, slopefloats: See expyfun.analyze.sigmoid for descriptions.