Bayes Theorem Calculator

Enter a prior probability, P(B|A), and P(B|not A) to calculate P(A|B) and inspect the evidence decomposition.

Prior P(A)

P(B|A)

P(B|not A)

—Posterior P(A|B)

—P(B)

—P(A∩B)

—P(not A ∩ B)

P(A|B)=P(B|A)P(A) / [P(B|A)P(A)+P(B|¬A)P(¬A)]

Core describe → test → interpret workflows

Use descriptive context first, choose the method that matches the design, then keep inputs, settings and result evidence reproducible instead of copying a p-value without its analysis recipe.

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Interpret statistical results in context

Use plots and descriptive summaries before formal tests. Check the sampling/design assumptions that matter for the chosen method, report effect size and uncertainty where available, and avoid treating a threshold such as p < .05 as proof of importance, causation, or truth. Browser calculations are educational/planning utilities, not domain-specific professional advice.

How to use this Bayes Theorem Calculator

Enter a prior probability, P(B|A), and P(B|not A) to calculate P(A|B) and inspect the evidence decomposition.