Bean machine
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The bean machine, also known as the quincunx, is a device invented by Sir Francis Galton to demonstrate the law of error and the normal distribution.
The machine consists of a vertical board with interleaved rows of pins. Balls are dropped from the top, and bounce randomly left and right as they hit the pins. Eventually, they are collected into one-ball-wide bins at the bottom. The height of ball columns in the bins approximates a bell curve.
See also
External links
- A longer article on Sir Francis Galton and the bean machine (http://www.maps.jcu.edu.au/hist/stats/galton/galton16.htm)
- Another simulation, with explanations http://www.ms.uky.edu/~mai/java/stat/GaltonMachine.html
- Yet another simulation, from John Carroll University http://www.jcu.edu/math/isep/Quincunx/Quincunx.htmlnl:Quincunx