Why Buy a Quincunx?

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".