First repeat

[FreeRoulette]

Anyone have stats on the average number of spins until the first repeat number?

[TurboGenius]

On average, how many trials would you need in 38-number roulette before any number is repeated?



Counting the first trial, I show the mean is 8.408797, the median is 8, and the mode is 7.

The probability of two numbers without a repeat is 37/38 = 97.37%.

The probability of three numbers without a repeat is (37/38)×(36/38) = 92.24%.

The probability of four numbers without a repeat is (37/38)×(36/38)×(35/38) = 84.96%.

Following this pattern, the probability of no repeats in 8 numbers is (37/38)×(36/38)×(35/38)×...×(31/38) = 45.35%.

So the probability of a repeat within 8 numbers is 100% - 45.35% = 54.65%.

I suspect most people would estimate that that probability of a repeat within 8 numbers would be less than that. If you’re not above taking advantage of your math-challenged friends, propose a bet that it will take 8 or fewer numbers for at least one to repeat. So you would be betting on 8 or fewer, and your friend 9 or more. If he/she balks, then offer to take 7 or over, which would have a 55.59% chance of winning. Basically, whichever side covers the median of 8 is likely to win.

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link:://wizardofodds.com/ask-the-wizard/roulette/

[FreeRoulette]

Thank you TurboGenius!

I was hoping I could bet 8 numbers and cover all numbers until a repeat using some progression.

[TurboGenius]

You can try - but for the record I have seen 20+ spins without a repeat and that would kill a progression.

[FreeRoulette]

The outliers would definately kill me. I have to hit the sweet spot and hope the wins overcome the losses.

[TurboGenius]

by "sweet spot" you mean you would have to pick what numbers to play based on something more than "luck" I hope
Then you might just have something worth digging into. 

[FreeRoulette]

I mean like if 8-15 spins captures 75% of the repeats. Then I would play that range.

[Rolletti]

This guy plays something similar on the last 8-9 numbers.
But he plays not the first to repeat, he tracks a bunch of numbers before the betting starts. Maybe it is some advanced selection.

link:s://youtu.be/dvqiSXZ4BCg

Cheers Rolletti

[Blood Angel]

I have been studying this way of playing for some time. I have a set of 37 spins where there were 26 unique before the first repeater. Rare yes, but something to bear in mind!

BA

[FreeRoulette]

Another thing I need to check out is the repeat rate on the coldest 8 numbers.