Randomness tests

Quick sanity checks for a random sequence: chi-square, runs test, autocorrelation, and normality.

Runs locally in your browser. Input data is not uploaded. These tests do not prove cryptographic security.

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How to use (3 steps)

  1. Paste a bit sequence (0/1) or a list of numbers (whitespace/CSV).
  2. Choose settings and click Run tests.
  3. Review p-values and charts, then copy a settings-only URL or download a report.

Check bias and structure

Randomness test tool

Chi-square checks uniformity, runs checks switching, and ACF checks simple dependence (not a full test suite).

Tip: You can drag & drop a .txt/.csv file onto the sequence box.

Samples

Settings

Tests to run

Results

Chi-square


          

Runs test


        

Autocorrelation


          

Normality (Jarque–Bera)


        

How to use this tool effectively

This guide helps you use Randomness tests in a repeatable way: define a baseline, change one variable at a time, and interpret outputs with explicit assumptions before you share or act on results.

How it works

The page applies deterministic logic to your inputs and shows rounded output for readability. Treat it as a comparison workflow: run one baseline case, adjust a single parameter, and measure both absolute and percentage deltas. If a result seems off, verify units, time basis, and sign conventions before drawing conclusions. This approach keeps your analysis reproducible across teammates and sessions.

When to use

Use this page when you need a fast estimate, a classroom check, or a practical what-if comparison. It works best for planning and prioritization steps where you need direction and magnitude quickly before investing in deeper modeling, manual spreadsheets, or formal external review.

Common mistakes to avoid

Interpretation and worked example

Run a baseline scenario and keep that result visible. Next, modify one assumption to reflect your realistic alternative and compare direction plus size of change. If the direction matches your domain expectation and the size is plausible, your setup is usually coherent. If not, check hidden defaults, boundary conditions, and interpretation notes before deciding which scenario to adopt.

See also

Frequently asked questions

Does passing these tests prove true randomness?
No. These are simple sanity checks. Passing does not prove cryptographic security, and failing can happen by chance or due to mismatched assumptions.
Is my input uploaded to a server?
No. Everything runs locally in your browser.
Why can chi-square fail for normal-distributed data?
This chi-square test checks uniformity over a range. A normal distribution is not uniform, so it can fail by design.
How large should my sample be?
Larger samples are more stable. For chi-square, keep expected counts per bin sufficiently large (a common rule of thumb is at least 5).
Which test should I use for normal-distributed samples?
Use the normality check (Jarque–Bera) to test whether your numbers look consistent with a normal distribution. The chi-square test on this tool checks uniformity, not normality.

How to use Randomness tests effectively

How this tool helps

Tools are designed for quick scenario comparisons. They work best when you keep one question per run, define success criteria first, and avoid switching objectives mid-stream. This reduces decision noise and produces results you can defend in follow-up review.

Input validation checklist

Before running, verify that required values are in the right format, that optional flags are intentionally set, and that baseline assumptions reflect current conditions. Invalid assumptions are often mistaken for tool bugs, so validation is part of interpretation quality.

Scenario planning pattern

Build three rows: conservative, expected, and aggressive cases. Keep data sources transparent for each case and compare output spacing. The pattern helps you spot non-linear jumps and decide whether a model is stable under plausible variation.

When to revisit inputs

Revisit inputs when input scale changes, time window shifts, or downstream decisions add new constraints. If constraints change, your previous output remains a useful reference but should not be treated as final guidance.

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