36 // Deceptive Dice

`No,' says the statistician. `It's an observational error. On average, two and a half people went each way.'

`No, no, no,' says the mathematician. `It's perfectly obvious.

........................................... If someone goes in now, the building will be empty.'

Deceptive Dice The Terrible Twins, Innumeratus and Mathophila, were bored.

`I know,' said Mathophila brightly. `Let's play dice!'

`Don't like dice.'

`Ah, but these are special dice,' said Mathophila, digging them out of an old chocolate box. One was red, one yellow and one blue.

Innumeratus picked up the red dice.* `There's something funny about this one,' he said. `It's got two 3's, two 4's and two 8's.'

`They're all like that,' said Mathophila carelessly. `The yellow one has two 1's, two 5's and two 9's ­ and the blue one has two 2's, two 6's and two 7's.'

`They look rigged to me,' said Innumeratus, deeply suspicious.

`No, they're perfectly fair. Each face has an equal chance of turning up.'

`How do we play, anyway?'

`We each choose a different one. We roll them simulta- neously, and the highest number wins. We can play for pocket money.' Innumeratus looked sceptical, so his sister quickly added: `Just to be fair, I'll let you choose first! Then you can choose the best dice!'

`Weeelll . . . ' said Innumeratus, hesitating.

Should he play? If not, why not?

...........................................

Answer on page 260

* Strictly speaking, `dice' is the plural, and I should have used `die' ­

but I've given up fighting that particular battle. I mention this to

stop people writing in to tell me I've got it wrong. Anyway, the

proverb tells us `never say die'.

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