What are mutually exclusive events?

Mutually exclusive events are defined as events that cannot occur simultaneously; if one event happens, the other cannot happen at the same time. For example, when flipping a coin, the outcomes "heads" and "tails" are mutually exclusive because the coin cannot land on both sides at once. This concept is important in probability because it helps to calculate the likelihood of different outcomes occurring; you can add the probabilities of mutually exclusive events together to find the total probability of either event occurring. In contrast, events that can happen at the same time are known as non-mutually exclusive events, meaning their occurrences do not affect each other.