ABSTRACT
Solving a scientific or an industrial problem usually involves mathematical analysis and/or simulation. To perform a simulation, we repeat an experiment a large number of times to assess the probability of an event or condition occurring. For example, to estimate the probability of at least one 6 occurring within four rolls of a die, we may do a large number of experiments rolling four dice and calculate the number of times that at least one 6 is obtained. Similarly, to estimate the fraction of time that, in a certain bank all the tellers are busy, we may measure the lengths of such time intervals over a long period X , add them, and then divide by X . Clearly, in simulations, the key to reliable answers is to perform the experiment a large number of times or over a long period of time, whichever is applicable. Since manually this is almost impossible, simulations are carried out by computers. Only computers can handle millions of operations in short periods of time.
