Log-Normal Distribution
Louis Theodore · 2015
Before proceeding to the presentation on log-normal distribution, the interests of the reader would be better served with several short introductory paragraphs on logarithms. The logarithm of a number is the exponent of that power to which another number, the base, must be raised to give the number first named. Any positive number greater than 1 might serve as a base. Two have been selected by the technical community. One base, 2.718 denoted by the letter e, gives rise to a system of logarithms that are conveniently applied in engineering and science. These are referred to as Napierian or hyperbolic logarithms. The other base used is 10, giving logarithms particularly adapted for use in computation, referred to by some as common or Briggsian logarithms. Tables of logarithms given without designation invariable refer to base 10. Since most numbers are irrational powers of 10, a common logarithm, in general, consists of an integer, which is called the characteristic and an endless decimal, the mantissa.1,2 The integration of some log terms arise in practice. Ten of these integrations with limits of 0-1 are provided in the following.