Today there is an increasing emphasis on the use of the ideas of probability theory in the simulation of a variety of models suitable for the description and interpretation of complex problems. These problems involve phenomena as remote and different as the number of arrivals or the average waiting time in a queuing process, the yield of cotton from a number of different plots of land and the standard of quality of the items manufactured by a certain process. There is a property that is possessed in common by such phenomena that enables probability theory to have different applications. The property is such that each of these phenomena that enables probability theory to have different applications. The property is such that each of these phenomena may be considered as a random phenomenon in the following way...