## A Conversation for What do Probabilities Mean?

### Something that's always bugges me...

Silly Willy Started conversation May 31, 2001

Using the National Lottery as an example.

The mathematical chances of the sequence 3,23,34,45,21,12 coming up is equal to the chances 1,2,3,4,5,6 coming up.

Surely that's not true because the moment you predefine a number sequence the chances of it coming up are reduces or something.

In fact when I come to write this down it sounds as though I may just have gone mad.

### Something that's always bugges me...

Martin Harper Posted May 31, 2001

> "The mathematical chances of the sequence 3,23,34,45,21,12 coming up is equal to the chances 1,2,3,4,5,6 coming up"

Yep - that's perfectly true.

BUT the mathematical chance of a straight (IE, 3,4,5,6,7,8 or 40,39,38,37,36,35) coming up are very very small compared to a non-straight coming up.

Does that help?

### Something that's always bugges me...

Gavin Orr Posted Aug 27, 2006

Another way to think about it (I think!) is to look at "coin tossing"

The chances of throwing heads on a single throw is 1 in 2, so the chances of throwing six heads in a row is 1 in 64,

BUT, if you have already thrown five heads in a row, the chances of you tossing heads again is 1 in 2. (Because the 62 other combinations of heads and tails out of the original 64 have been rendered impossible, by the five tosses already taken.)

I play lotto (in Australia, where division 1 is paid out for six number out of 44). One of my bets is 1,2,3,4,5,6 another is 7,8,9,10,11,12 , a third is 13,14,15,16,17,18 (you get the idea).

While it seems weird, the chance of me winning lotto betting these numbers is just the same as the chance of any other set of six (if you are interested, the chance of wining 1st division lotto in Australia with one bet is 1 in 7,059,052)

The reason I bet sequential numbers is that I reckon fewer people do this than bet non-sequential numbers (and this assumption is supported by your original post). So while the chance of me winning is no better than anyone else, if fewer people are likely to bet the same numbers as I, then I am less likely to have to share the big prize when I do win.

Manybe I shouldn't be saying this, since if enough people realise the odds are the same, they might start picking sequential numbers, 'cos it's much quicker to fill in the form (:->

Keep Bookcrossing --> www.bookcrossing.com

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