Can someone explain how the RoR is figured? Everything I have read seems to say you need a BR of 1/1000th of your original bet. I would assume that having a larger bankroll would decrease the RoR even more and I'm curious as to why 1/1000th is the magic number? What is the RoR if it is 1/2000th, 1/500th or 1/100th?
Spreads???? What is common to use, what is necessary to be profitable?
Thanks again,
Gibby
Spreads are dependant on the game, like # of decks and penetration. If you have bad penetration, you'll have to spread more. If you have more decks, you'll have to spread more. If you have worse rules, you'll have to spread more. If you're playing a double deck game, with DAS, LS, and other good rules along with 80% pen, you won't have to spread that much. If you're playing double deck with nDAS, no surrender, and 60% pen, you'll have to spread much more. A 6deck spread might be 1-12, 1-16, or 1-24. For 2deck, you might need to spread 1-3, 1-5, or 1-8. If you're playing single deck, the most you can probably get away with is a 1-3 spread (or at least that's what I've read).
"Everyone wants to be rich, but nobody wants to work for it." -Ryan Howard [The Office]
Interesting, I didn't know that (about it being compared to 2x'ing your BR). So, does that mean that if your ROR is 1%, then the chance you'll double your BR is 99%? Or does it not quite work like that?Originally Posted by zengrifter
"Everyone wants to be rich, but nobody wants to work for it." -Ryan Howard [The Office]
It can be risk of losing your bankroll before doubling, or just the risk of losing your bankroll ever, depending on context. If your RoR is 1%, that implies a 99% chance that you do not reach ruin. That means, under the former definition, you have a 99% chance of doubling your bankroll (if you play long enough). Under the latter definition, it means there is a 99% chance that you do not reach ruin ever, and your win will approach infinity. Obviously, once your bankroll has doubled a few times, if you don't change your strategy at all, your odds of then losing everything are infinitesimally small. Practically speaking, if your risk of ruin before doubling is reasonable, your overall risk of ruin (without the doubling constraint) will also be reasonable, since it is not likely to double your bankroll and then lose everything.
Where do Standard Deviations play into ROR? On the "ROR Calculator" on qfit, there's a place to enter your standard deviation (and what does that SD mean?). Is it something like, "If you are within 1 standard deviation, then you have a 5% chance of ruin." ?? This is one thing I don't enjoy about BJ, it's difficult to figure out what all this different stuff means....and it seems like everyone has a different idea or understanding. =\
"Everyone wants to be rich, but nobody wants to work for it." -Ryan Howard [The Office]
More generally, if the RoR for bankroll B is X, then the RoR for bankroll A*B, without changing your betting or playing strategy, is X^A. This formula is only true for long term risk, not session risk with a limited time horizon. In the case you bring up here, you are talking about losing half of B, so A=0.5 and the RoR is X^0.5 (this is equivalent to sqrt(X)). This works for any number A and can be useful when you know the RoR for a specific game but are confronted with a different situation in the field without access to your computer. As an example, say there is a good promotion and you intend to flat bet the max of $50, and you've calculated ahead of time that your RoR for that bet is 0.5%. But you get to the casino and find that you can actually bet $100. Now you don't need to go back to the car to figure out your risk. Since you are doubling your bet size, you are halving the size of your bankroll in number of bets, so you can use sage's formula and your RoR will be sqrt(0.005)=0.0707, or 7.1%. This is the same as (0.005)^(0.5)=0.0707. What if instead of $100 you can bet $75? This is where the more general formula is useful. The number of bets in your bankroll was BR/50 and now it is BR/75, so your BR is 2/3 as big (A=2/3). If your RoR for $50 bets was again 0.5%, your new RoR for $75 bets is (0.005)^(2/3)=.029, or 2.9%. It's not a formula I use often, but it's a good one to understand conceptually.
Interesting stuff, thanks for the info sage & Nyne. So, say I have 10K BR with a 10% ROR (or 0.1 ROR). If I increase that to 20K, then the ROR would be 0.1^2 (the 2 because BR is x 2), to bring the ROR to 0.01, or 0.1% ? If I take that 10K BR, and lose half, so it's at 5K (or 10K x 0.5), then the ROR would be 0.01^0.5 = 0.31... = 31% ?! Damn, that's good to know.
"Everyone wants to be rich, but nobody wants to work for it." -Ryan Howard [The Office]
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