In probability, what does it mean if two events are said to be exhaustive?

When two events are described as exhaustive, it means that they encompass all possible outcomes of a particular scenario. In other words, the combination of these events ensures that at least one of them must occur, leaving no possibilities unaccounted for. This is particularly important in probability because it allows for a complete understanding of the entire sample space.

For instance, consider a simple scenario involving the flipping of a coin. The exhaustive events in this case would be "heads" and "tails." Together, they include every possible outcome when flipping a coin, as one of these must happen every time.

This concept is crucial in probability calculations, as it allows for a comprehensive view of outcomes, enabling accurate probability assessments. The other options describe different relationships or characteristics of events but do not capture the essence of what it means for events to be exhaustive.