Bayes theorem calculator

Calculate posterior probability with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use posterior probability to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Prior probability
0.1
Evidence likelihood given hypothesis
0.8
Evidence likelihood without hypothesis
0.2
Posterior probability
0.307692

Try another scenario

Prior probability
0.11000000000000001
Evidence likelihood given hypothesis
0.8
Evidence likelihood without hypothesis
0.2
Posterior probability
0.330827
Calculation method

Calculation method

Posterior probability

a × b ÷ (a × b+(1-a) × c)

Symbols and units
a
Prior probability
b
Evidence likelihood given hypothesis
c
Evidence likelihood without hypothesis

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • Uses Bayes’ theorem for a hypothesis and its complement.
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Further reading

Method reference ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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