Maths Question

[bwheatle]

My math is simply too rusty to even know whether or not there is an answer to the question.

I'm that old that I'd nearly forgotten the question I was about to ask.

Heard about the professional golfer who employed a 90 year-old caddie whose eyesight was sensational? Could see where his ball landed from 300 meters! Only problem was, when the caddie got to where his ball landed he'd forgotten!!

O.K. The serious Math question?

Taking roulette as an example, if I knew that red was going to land 72% of the time (well we all wish we could find a system like that) is there a mathmatical way of calculating a 'run of outs'? Is there a formula for calculating the chance that black numbers will land in succession two, three,four,five etc times in a row?

For the purpose of the example, forget '0's exist.

Any help would be appreciated from younger members of the forum.

[AssumeTheCrown]

Barry,

According to your data, Red will come up 72% of the time which means black must come up 28%(you said to ignore the green). You are calling black an "out" so assuming the spins are independant, any spin has a 28% or .28 chance of being an out. To work out the chance of x number of consequtive outs we multiply .28 x-times. So 3 outs in a row would be .28x.28x.28=.022 or a 2.2% chance that in any 3 spins a red does not appear. The probability of going 10 spins in a row without a red would be .28^10=.000003 which equates to 3 times out of a million you would expect to go 10 spins without a red.

Hope this helps.

PS Where can I find this roulette wheel?

[Bhagwan]

The answer to the longest run of outs of a 71% SR is 6.

[Mark]

.....until you hit 7.

:smile:

[La Mer]

The answer is literally a piece of string - it really depends on the number of trials, e.g. in a 100 spins the 'expected' longest losing run 3; in a 1,000 spins the 'expected' longest losing run is 5; in 10,000 the 'expected' losing run is 7; while in 100,000 the 'expected' losing run is 9.

As I said the answer is a piece of string and how long it is.

[kenchar]

Gotta agree with Mark and La Mer

[bwheatle]

Many thanks for your input guys, but just how long is that piece of string?

My 72% 'roulette wheel' is a simple place system that for tomorrow picks,

Canterbury Race 7 No 3
Sandown Race 3 No 2
Sandown Race 6 No 5
Eagle Farm Race 4 No 3

[shoto]

4 out of 4 there.