Probability is the branch of mathematics concerning numerical descriptions of how likely an event is to occur, or how likely it is that a proposition is true. The probability of an event is a number between 0 and 1, where, roughly speaking, 0 indicates impossibility of the event and 1 indicates certainty. To understand and measure the chance, we perform the experiments like tossing a coin, rolling a die and spinning the spinner etc. The experimental approach relies on the idea of simulating the real event and observing how often the various possible outcomes occur in the trial(s) to assess how likely any given outcome might be. Sometimes it so happens that we would have to predict the outcome without actually performing the actual experiment. The probability or likeliness of an event occurring, without actually experimenting, is called theoretical probability. Probability is a notion which we use to deal with uncertainty. If an event can have several outcomes, and we don't know for sure which outcome will occur, we can use probability to describe the likelihood of each of the possible events. The classic example is flipping a coin. Probability is the study of random events. Probability and statistics are closely linked because statistical data are frequently analysed to see whether conclusions can be drawn legitimately about a particular phenomenon and also to make predictions about future events.