Definition
Probability quantifies the likelihood of an event occurring, expressed as a number between zero and one. A probability of zero means an event is impossible, while a probability of one signifies certainty. In practice, probability helps us make informed decisions by assessing potential outcomes and their chances of happening. Understanding probability is crucial for risk management, allowing professionals to anticipate potential issues and develop mitigation strategies. For instance, a cybersecurity analyst might use probability to estimate the chance of a specific type of cyberattack occurring based on historical data. This differs from certainty, which implies an event will definitely happen or not happen. Probability concepts are frequently tested in domains like risk management and decision analysis on exams such as the PMP and CAPM.