30.1.107 LogNormal
Contents
Function
![y=y_0+\frac A{\sqrt{2\pi }wx}e^{\frac{-\left[ \ln \frac x{xc}\right] ^2}{2w^2}}](/origin-help/en/images/LogNormal/math-e98dcb616116ac2349df7544a55b124f.png?v=0 "y=y_0+\frac A{\sqrt{2\pi }wx}e^{\frac{-\left[ \ln \frac x{xc}\right] ^2}{2w^2}}")
Brief Description
Probability density function of random variable whose logarithm is normally distributed.
Sample Curve
Parameters
Number: 4
Names: y0, xc, w, A
Meanings: y0 = offset, xc = center, w = log standard deviation, A = area
Lower Bounds: xc > 0, w > 0
Upper Bounds: none
Derived Parameters
Mean: mu = exp(ln(xc)+1/2*w^2)
Standard Deviation: sigma = exp(ln(xc)+1/2*w^2)*sqrt(exp(w^2)-1)
Script Access
nlf_lognormal(x,y0,xc,w,A)
Function File
FITFUNC\LOGNORM.FDF
Category
Statistics, PFW, Peak Functions, Origin Basic Functions