Lottery Gaps

Taking another look at the UK National Lottery, David Spiegelhalter discusses the amazingly long gaps during which some numbers simply never appear.There's further reading at http://understandinguncertainty.org/node/39 where you can also play with the animation directly.

Category:

Gaming

Tags:

• lottery
• lotto
• 649
• chance
• league
• distribution
• chi
• bias
• ball
• number
• hot

[shockadelicaustralia]

What shape should we expect? Most likely "straight away"? Nonsense!

Each number should only appear once in 8 games. So the predicted bell curve should peak around 8, not 1. A ball should appear twice in 16 games, not twice in 2. That is incredibly *im*probable! Likewise not appearing for 72 games, almost 9 times under expected frequency.

Occuring twice in a row, or vanishing for 72 weeks is not "what you would expect" at all.

You would expect numbers to occur once in 8 games. And they don't

[askmagus]

Quite well explained.

Its things like this when, say playing roulette on TV they go, oooh, look at this, the hot numbers are x y and z... and 20 reds in a row.... It looks like the reds will keep on coming.

Basically this information is useless... UNLESS, there is something wrong with the wheel, (eg titled).

=^_^=

[singingbanana]

Great stuff!

[TyYann]

Excellent presentation.

[bluecobra95]

first, by the way.

[bluecobra95]

I now understand uncertainty! :)