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Bayesian Inference

How should evidence change your mind? Bayesian inference combines a prior belief with observed data to produce a sharper posterior — watch it update in real time.

Bayesian InferenceLive

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Bayesian inference updates a prior belief with data to form a posterior. For a coin, a Beta prior combined with binomial coin flips gives a Beta posterior — the conjugate update is just adding heads to α and tails to β. Watch the posterior sharpen and shift as evidence accumulates.

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Data Inspector

Posterior mean0.667
Posterior SD0.094
Posterior α, β16.0, 8.0

Governing equation

Reading this result: The posterior mean 0.667 sits between the prior mean 0.500 and the observed rate 0.700; with 20 flips versus 4.0 pseudo-counts, the data dominates and pulls the estimate toward the evidence.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

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How it works

Bayes' theorem multiplies a prior distribution by the likelihood of the data to get the posterior. For a coin's bias, a Beta prior and binomial data combine into a Beta posterior via a simple conjugate update: add heads to α and tails to β. As data accumulates, the posterior narrows and overrides the prior.

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Frequently asked questions

Is this Bayesian inference simulator tool really free?▾
Yes. Bayesian Inference runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?▾
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.