Which rule states that the probability of either event A or event B occurring is calculated by adding the probabilities of each event and subtracting the probability of both occurring?

The General Addition Rule is a fundamental principle in probability that allows you to determine the likelihood of either event A or event B happening. According to this rule, the probability of either event occurring is found by adding the probabilities of the two events together. However, if there is a possibility that both events could occur simultaneously, you must subtract the probability of both events happening to avoid double counting.

This is particularly important in scenarios where the two events are not mutually exclusive—meaning both can happen at the same time. By accounting for the overlap, you ensure that the combined probability reflects the true likelihood of either event occurring.

For example, if event A represents the probability of drawing a red card from a deck and event B represents the probability of drawing a face card, the General Addition Rule helps you calculate the overall probability of drawing a card that is either red or a face card, considering there are red face cards that would otherwise be counted twice.

This rule is foundational in probability theory and is directly applicable in various statistical analyses, making it essential knowledge for any statistics course.