quincunx

A Galton board. Every ball bounces left or right at each peg; the bin it lands in counts how many times it went right. Drop enough of them and the bins trace the binomial distribution, and on a tall board, the normal curve.

balls in each bin exact expected count normal curve

Drop

Speed

Board Rows 12 Row pattern Chance of bouncing right 0.50

Exact expected counts Normal curve

So far

Balls: 0
Mean bin: – expected 6.00
Spread (sd): – expected 1.73
Distance from exact: – typical –
Chi-square test: –

Getting closer

distance from exact after each drop typical distance, falling like 1/√N