Probability lab

Chance Lab

Flip a coin or roll dice, then watch the histogram chase the dashed theory line. Small samples lie. Large ones settle.

Idle

Histogram

Solid bars are observed. Dashed ticks are theoretical.

  • Observed
  • Expected

Tap a bar for the expected share. Run trials to fill them in.

Share of heads

Shaded band is a typical range (±2 standard errors). It narrows like 1/√n.

0%50%100%n = 1n = 100

No average yet

Trials

0

Distance

—

Total variation from theory

Typical error

—

About 1 / √n

Share of heads

—

Theory 50.0%

Theory is a map, not a promise

A fair coin is 50/50 in the long run. The next flip is still a coin flip. Run trials and watch the bars try to catch the dashed line.