Logistic Function Calculator

Posted by Dinesh on

Online probability calculator helps to calculate exponential growth probability using logistic function formula.

The logistic function is often used to fit a measured psychometric function. This is because it has the right general properties. It starts at 0 and increases to 1 in the sigmoidal manner characteristic of measured psychometric functions.

Fitting the logistic function

The reason for fitting a logistic function to your measured psychometric functions is to get a more accurate estimate of the true threshold. Each individual fraction longer judgment will have some error. By fitting the logistic, we can smooth the error to get a better estimate of what is going on.

Calculate Exponential Growth Probability

Formula:

p(x) = L ÷ [1 + e-k(x-x0)]

where,
L = curve's maximum value,
e = the natural logarithm base (i.e., 10),
x0 = determines at which duration the midpoint occurs,
x = duration,
k = the steepness of the curve,
p(x) = Logistic function probability that duration x will be judged as longer than the standard duration.