How do I simulate a Bayesian update?

Open this page and use the live A/B Test tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.

Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.

Can I use my own numbers?

Absolutely — every input is adjustable, and with data import you can drive a Bayesian update from your own measurements.

Use case · powered by A/B Test

A/B Test for a Bayesian update

Simulate a Bayesian update live in your browser. This runs the real A/B Test solver — adjust the inputs, watch it respond instantly, and export the result. No install, no account.

For:Students Researchers Educators Engineers Hobbyists & Makers K-12 Students First Responders

A/B Test SignificanceLive

two-proportion z-test

Controls

Presets

A visitors

A conversions

B visitors

B conversions

An A/B test compares two conversion rates to see if a difference is real or just noise. The two-proportion z-test pools the data to estimate the standard error, then a p-value below 0.05 signals a statistically significant difference. Bigger samples separate the two curves and make small lifts detectable.

▶ Run in Python

Data Inspector

Rate A10.00%

Rate B12.50%

Lift+25.0%

p-value0.0769

Resultnot significant

Governing equation

z = \frac{p ^ _{B} - p ^ _{A}}{p ^ ( 1 - p ^ ) ( \frac{1}{n _{A}} + \frac{1}{n _{B}} )} = \frac{0.025}{0.113 \cdot 0.887 ( \frac{1}{1000} + \frac{1}{1000} )} = 1.77

Reading this result: B looks 25.0% different, but with only 2,000 visitors p=0.077 — the sample is too small to call it real yet.

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

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About this simulation

The full A/B Test tool models a Bayesian update with the same numerics engineers and scientists use — running entirely client-side. Change any parameter and the result updates in real time, so you can build intuition, check a design, or teach the concept without spreadsheets or installs.

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Frequently asked questions

How do I simulate a Bayesian update?: Open this page and use the live A/B Test tool below — set your inputs and the simulation runs instantly in your browser using real numerics. No install, no account needed.
Is it free?: Yes. The simulation runs free in your browser. A one-time unlock or a Pro plan adds advanced parameters, saved presets, data import, and clean exports.
Can I use my own numbers?: Absolutely — every input is adjustable, and with data import you can drive a Bayesian update from your own measurements.