Specifies a lognormal distribution with the entered mean and standard deviation. The arguments for this form of the lognormal distribution specify the actual mean and standard deviation of the generated lognormal probability distribution.

f(x,mu,sigma) = exp (-0.5 * ( ( log(x)-mu_h)/sigma_h ) ^2 ) / ( x * sqrt(2 * pi ) * sigma_h )

where   

mu_h = log(mu^2/sqrt(sigma^2+mu^2))   

sigma_h = sqrt(log(1+(sigma/mu)^2))

support 0 ⇐ x ⇐ Inf