# Posterior Probability

> Source: https://sukruyusufkaya.com/en/glossary/posterior-olasilik
> Updated: 2026-05-13T21:00:30.735Z
> Type: glossary
> Category: matematik-istatistik-optimizasyon
**TLDR:** A Bayesian probability concept representing updated belief after observing new data.

<p>Posterior probability is the central concept in Bayesian reasoning. It represents how likely a hypothesis is after new data has been observed. It combines prior knowledge with evidence to produce an updated belief. This makes uncertainty dynamic rather than static, allowing the system to revise its beliefs when new information arrives. Posterior calculations are critical in medical diagnosis, risk analysis, filtering systems, and Bayesian machine learning. The posterior is, in a sense, the mathematically updated form of learning.</p>