Posted by John Bibby, QED of York England on 9th Apr 2015
Why Buy a Quincunx?
John Bibby, QED of York, York, England (qed@enterprise.net)
As one who has actually TRIED building a quincunx, I can only say
it's hellishly difficult: my contraption looked quincunxy, but the
distributions produced were far from normal.
I am left concluding (a) I'm frightfully cack-handed, or (b) Galton
had a fine crafts-team (probably both).
Incidentally, Galton's original quincunx was in the Pearson Building
at University College, London in the 1960's, but now it has gone.
Does anyone know where it is now?
Steven Stigler gives a marvellous discussion if Galton's Q in his
"History of Statistics". This includes a fine demonstration
of how conditional arguments can be used to derive complex results
such as "A normal mixture of normal distributions is itself normal".
Galton is also discussed in Theodore Porter's "The Rise of
Statistical Thinking".
By: Steve Moore, Wausau PapersSir Francis Galtonʼs invention can do more than just demonstratenormal distribution.The purpose of this article is to give you an appreciation of theQuincunx as an educational tool for teaching some of the theory behindthe tools and concepts of so-called modern quality management. TheQuincunx is often seen in the possession of organizations [...]
The Quincunx (pronounced quinn-cux) or bead board, as some call it, was developed by a mathematician named Galton in the late1800's. The device works by dropping a series of acrylic balls, or beads, through rows of located pins. Each bead, as it hits a pin, has a 50-50 chance of falling to the left or [...]
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