Probability is a measure of the likelihood of an event to occur. Many events cannot be predicted with total certainty. We can predict only the chance of an event to occur, how likely they are to happen, using probability. A probability is a real number between 0 and 1 that describes how likely it is that an event will occur. A probability of 0 means that an event will never occur. A probability of 1 means that an event will always occur. A probability of 0,5 means that an event will occur half the time or one time out of every 2. The concepts which are explained here are some of the terms related to probability and operations. “Probability is a measure of the possibility that an event will occur”. It is qualified as a number between zero and one. A simple example of probability is tossing of the coin. A coin consists of two sides, head and a tail, which means there are only two outcomes. The probability of tails equals the probability of heads. The probability of tails or heads is 1/2 since there are no other outcomes.