stochastic

1) Generally, stochastic (pronounced stow-KAS-tik, from the Greek stochastikos, or "skilled at aiming," since stochos is a target) describes an approach to anything that is based on probability.

2) In mathematics, a stochastic approach is one in which values are obtained from a corresponding sequence of jointly distributed random variables. Classic examples of the stochastic process are guessing the length of a queue at a stated time given the random distribution over time of a number of people or objects entering and leaving the queue and guessing the amount of water in a reservoir based on the random distribution of rainfall and water usage.