AI engineering glossary · Probability
What is prior probability?
Prior probability: The probability assigned to an event or parameter before seeing the new evidence, reflecting earlier knowledge or assumption. In Bayes' theorem it is the starting belief that gets updated. It is combined with new data to produce an updated belief.
Prior probability: an example
Before testing, you assume 2% of transactions on a payments app are fraudulent; that 2% is the prior.
Related terms
More Probability terms
- Probability
- Probability axioms
- Probability density function
- Probability distribution
- Probability mass function
- Quantile
- Random experiment
- Random sampling
Where you learn it
Prior probability is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.