Bayes' Theorem Calculator
Calculate posterior probability using Bayes' theorem with prior probability and likelihood
About this calculator
The Bayes' Theorem Calculator helps you determine posterior probability by combining prior probability with new evidence or likelihood. This fundamental statistical tool is essential for decision-making in medicine, finance, machine learning, and scientific research. By updating your initial beliefs with observed data, you can make more accurate predictions and informed decisions based on probabilistic reasoning.
How to use
Enter your prior probability (initial belief before new evidence), the likelihood of observing the evidence given your hypothesis is true, and the total probability of the evidence occurring. The calculator will compute the posterior probability using Bayes' formula, showing how the new evidence updates your original belief.
Frequently asked questions
What is Bayes' theorem used for?
Bayes' theorem updates probability estimates when new evidence becomes available, commonly used in medical diagnosis, spam filtering, and predictive analytics.
What's the difference between prior and posterior probability?
Prior probability is your initial belief before evidence, while posterior probability is the updated belief after incorporating new evidence.
Can posterior probability be higher than prior probability?
Yes, if the evidence strongly supports your hypothesis, the posterior probability can be significantly higher than the prior probability.