ABSTRACT
Exponential distributions are encountered as life-time distributions with constant hazard rate. Exponential distributions are commonly employed in the formation of models of lifetime distributions, and stochastic processes in general. Even when the simple mathematical form of the distribution is inadequate to describe real-life complexity, it often serves as a bench-mark with reference to which effects of departures to allow for specific types of disturbance can be assessed. Exponential distributions also appear as distributions of squared aiming errors in two dimensions when the error is the resultant of independent homoscedastic and unbiased errors in horizontal and vertical directions. Despite being a special case of the gamma family of distributions (Type III) discussed by Karl Pearson as early as 1895, it took another three-and-a-half-decades for the exponential distribution to appear on its own in the statistical literature.
