Probability bench

What should happen—and what happened this time?

Probability describes the source. A sample is one noisy piece of evidence from it. Load the coin to feel the difference.

Hands-on evidence

Load the coin

Change the odds, then compare what the source promises with what a short run happens to produce.

50%
100

Run #1. More flips usually pull the observed share toward the source’s true bias—but never make it exact.

Expected heads50%The source model
Observed heads49.0%49 of 100 flips
Shannon entropy1.000Average surprise, bits/flip
Min-entropy1.000Worst-case guess, bits/flip
Sample closeness to the expected share: 95%

Observed gap: 1.0 percentage points. The bar is a teaching scale, not statistical confidence.

  • Tails
  • Tails
  • Tails
  • Heads
  • Heads
  • Heads
  • Tails
  • Heads
  • Tails
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  • Tails
  • Tails
  • Heads
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  • Heads
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  • Heads
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  • Heads
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  • Heads
  • Heads
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  • Heads
  • Heads
  • Heads
  • Tails
  • Heads
  • Tails
  • Heads
  • Heads
  • Tails
  • Tails
  • Heads
  • Tails
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  • Heads
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  • Heads
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  • Heads
  • Heads
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  • Heads
  • Heads
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  • Heads
  • Tails
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  • Tails
  • Heads
  • Heads
  • Heads
  • Tails
  • Heads
  • Heads
  • Tails
  • Tails
Balanced source

A fair source gives both outcomes equal weight. Bias lowers min-entropy because an attacker will always try the more likely answer first.

Simulation only. Every run is generated from a fixed teaching seed so the evidence can be replayed.