INTRODUCTION Historically, the theory of probability began to develop with the study of games of chance such as roulette and cards. Apart from games, uncertainty also prevails in other walks of life such as business, economy, and even in day-to-day activities.

Probability is a concept which numerically measures the degree of uncertainty and, therefore, of certainty of the occurrence of an event.

Before defining some terms related to probability, we shall give certain concepts used therein.

EXPERIMENT An operation which can produce some well-defined outcomes is known as an experiment.

In science or engineering if we perform an experiment and repeat it under identical conditions, we get almost the same result every time. Such experiments are called deterministic experiments.