a special type of probability distribution of random variables. If X has a normal distribution and if Y = ex, then Y will have a lognormal distribution characterized by the density
Here, m and σ are the parameters of the distribution of the variable X. The mathematical expectation Y is
mY = em + σ2/2
and the dispersion,
The sizes of particles of a crushed material (a rock, for example) and the content of many minerals in rocks obey this distribution to a good approximation.
V. I. BITIUTSKOV