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Originally Posted by TLD
But I am curious about your challenge even if he isn’t. You said: “I'd propose a minimum amount of bets you'd need to make, based on some total maximum bankroll you could spend. I'd be betting you that your returns would be statistically no better than break even.”
But isn’t there an obvious problem here? Why wouldn’t he just do some Martingale type thing to make it almost certain he’d win?
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Certainly Martingale would be a good choice if his were to strictly come out ahead using an arbitrarily large bankroll over a sufficiently small betting requirement (I talked about most recently in my
last post on the Martingale.)
Quote:
Originally Posted by TLD
Betting strategies like that don’t change the long run negative EV, but surely they affect the likelihood of winning or losing a given session. Instead of having a slightly below 50-50 chance of winning, with the winning and losing sessions being about the same size on average, you can easily structure your bets to have a 70% or 90% or 95% or whatever chance of winning, just with the drawback that when you do have a losing session, it’ll be many times bigger on average than your winning sessions. But if you’re talking about an even money bet that he just has to do better than break even to win, it doesn’t seem like he’d have much trouble collecting.
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You're definitely asking a very interesting question (although probably not so interesting to those who missed the original thread -- not that I'd recommend anyone head to the RX, but hey you know where to look). I really do wish I had come across your question earlier in the "night" before I had gotten hung up on some new project.
Anyway, I'll give you the very quick answer that probably won't be all that satisfying, but it was certainly what I had in mind in anticipation of what I assumed the slim possibility that Mr Ohio (wasn't he on some VH1 reality show, btw?) would have accepted.
So here's what I said, "I'd be betting you that your returns [would] be statistically no better than break even.”
Now this isn't to say that he would lose a lot of money, or even any money, what it's saying is that he'd be unable to produce enough evidence that to reject null hypothesis that his strategy has positive expectation. Obviously, we'd need to agree on a certain level of significance and I'd certainly have settled for 2 standard deviations above the mean, meaning that if he actually were expected to break even, then strictly by chance we'd see him pass the test 2.275% of the time.
So does that mean he's fairly be a roughly +4,296 dog to win the bet? No. Not even that.
Remember, he's not expected to breakeven he's expected to actually
lose (the house edge). And the more stake he were to risk, the more of it he'd expect to lose. That itself would serve as an additional fail-safe mechanism. As the notional size of the bet were to increase so too would the requirement as to how much he'd need to wager in order to complete the meta-bet. In that manner, while he'd only to perform 2 sigmas better than breakeven, he could very well be battling to attain a 2.5, 2.75, 3, or even higher sigma occurrence. While you're certainly correct that the Martingale is effective at transforming small, frequent losses into large infrequent ones, the limiting factor will still be the bankroll.
So in terms of a generic testing structure, it would look something like this: he would need to wager a certain amount (all else being equal, ideally a collar ... rather than a one-sided limit) at a certain table and when he finished the wagering requirement he'd need to have won a certain amount.
But how to determine the wagering requirement?
Put simply, the more he were allowed to bet the higher his requirement would be. If he were playing at an $X max table with an $X bankroll, he'd have a higher wagering requirement than if he were playing at $0.1X max table with an $X bankroll.
So if he were to give me a bankroll and a table limit, then I'd come back to him with a wagering requirement.
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Originally Posted by TLD
I assume you would block a strategy like that in the way you specify the details of the “minimum amount of bets” and the “total maximum bankroll,” but how? Could those things be restricted so radically that no strategy would be more likely than not to do better than break even?
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Obviously so. Look at a limiting case: you're playing at a table with $1,000 limits and you need to wager $295 centillion dollars. Good luck. The idea here is that while $295 centillion is clearly ridiculous, what about $14 quadrillion? Or $9 trillion? Or $6 million? At some point we get to a figure where the probability of betting through that amount and coming up 2 sigmas ahead of breakeven is right around a 2.5 - 3 sigma event.)
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Originally Posted by TLD
And if so, wouldn’t that make just about any strategy people like him believe in unavailable for the challenge, and hence result in him crying foul at your arbitrary rules? (“I just said I can win betting my way. I never said I can win with all these silly restrictions on my bets that no casino in the world places on its customers,” etc.)
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Probably. But that's the nature of the beast. Just ask
James Randi. You wouldn't believe some of the excuses people to avoid his challenges.
But the truth is that the rules really are rather open. He could bet any way he wanted and could take as many "good luck" breaks as he needed. I'd make every effort to structure the test to meet whatever requirements he had. The only stipulation would be that he come out ahead to a statistically meaningful extent -- and that benchmark would of course vary as function of the test itself. We're not testing whether he can get lucky after all, we're testing whether he can perform in fashion superior to what we might expect through chance alone.