Bayes' theorem, also called Bayes' rule or Bayesian theorem, is a mathematical formula used to determine the conditional probability of events. The theorem uses the power of statistics and probability ...

Having a strong opinion about an issue can make it hard to take in new information about it, or to consider other options when they’re presented. Thankfully, there’s an old rule that can help us avoid ...

It’s estimated that human adults make about 35,000 decisions a day — the percentage of good decisions depends on the adult. These choices can be as banal as deciding to roll or crumple toilet paper or ...

When Bob flips a coin and announces the result, what can we really know about which coin he chose? This video builds probability trees to reveal how new evidence systematically updates our beliefs, ...

Daniel McNulty began writing for Investopedia in 2012. His work includes articles on financial analysis, asset allocation, and trading strategies. Marguerita is a Certified Financial Planner (CFP), ...