risk of ruin question

[DSchles]

"it would be really neat if there was a formula that gave the # plays necessary for results to catch up with e.v."

You need to read BJA3 much more carefully.

In any event, the formula is child's play. Form the ratio of s.d./e.v. for, say, one hour's worth of blackjack play (100 hands). Then square the result. The answer is the number of hours required for e.v. to catch up to s.d. Example: Suppose hourly e.v. is 1.5 units and s.d. is 30 units. 30/1.5 = 20. 20^2 = 400. In 400 hours, e.v. will catch up to s.d.

Demonstration: e.v. for 400 hours will be 400*1.5 = 600 units. S.d. for 400 hours will be sqrt(400)*30 units = 20*30 = 600 units. Q.E.D.

Don

 

[sagefr0g]

"it would be really neat if there was a formula that gave the # plays necessary for results to catch up with e.v."

You need to read BJA3 much more carefully.

In any event, the formula is child's play. Form the ratio of s.d./e.v. for, say, one hour's worth of blackjack play (100 hands). Then square the result. The answer is the number of hours required for e.v. to catch up to s.d. Example: Suppose hourly e.v. is 1.5 units and s.d. is 30 units. 30/1.5 = 20. 20^2 = 400. In 400 hours, e.v. will catch up to s.d.

Demonstration: e.v. for 400 hours will be 400*1.5 = 600 units. S.d. for 400 hours will be sqrt(400)*30 units = 20*30 = 600 units. Q.E.D.

Don

please don't take this the wrong way. I freely admit that I've not read BJA3 all the way through. only really ever skim read (sometimes a bit concentratedly). just me maybe, I can't or wont, lol, at times it would be like reading those old white page and yellow page phone books that used to hang in phone booths. as an aside it's rumored Einstein did in fact read a phone book. for pretty much the same reason, I gave up counting cards, it's like reading one of those old phone books to me or even the Bible where it goes on and on about who begat who sorta thing. that said, I love the book, lol.
so but anyway, I guess another part of BJA3 that I need to read more carefully is (heaven forbid) the formula on page 136 and 137 ?
omg! that's got those trigonometry thinga magigs in it! I almost quit college over trigonometric thinga magigs. only thing worse was analytic geometry.
but ok, rant over lol, thank you for the clue far as a formula that gave the # plays necessary for results to catch up with e.v.

 

[sagefr0g]

For per-play values I have found that they yield the same result to within several decimal places.

it's probably me improperly rounding, I guess.

 

[DSchles]

please don't take this the wrong way. I freely admit that I've not read BJA3 all the way through. only really ever skim read (sometimes a bit concentratedly). just me maybe, I can't or wont, lol, at times it would be like reading those old white page and yellow page phone books that used to hang in phone booths. as an aside it's rumored Einstein did in fact read a phone book. for pretty much the same reason, I gave up counting cards, it's like reading one of those old phone books to me or even the Bible where it goes on and on about who begat who sorta thing. that said, I love the book, lol.
so but anyway, I guess another part of BJA3 that I need to read more carefully is (heaven forbid) the formula on page 136 and 137 ?
omg! that's got those trigonometry thinga magigs in it! I almost quit college over trigonometric thinga magigs. only thing worse was analytic geometry.
but ok, rant over lol, thank you for the clue far as a formula that gave the # plays necessary for results to catch up with e.v.

Norm has free online calculators for all the different ROR formulas in BJA3. You don't have to calculate anything.

Don

https://www.blackjacktheforum.com/resourcespage.php?do=calcpage

 

[sagefr0g]

Norm has free online calculators for all the different ROR formulas in BJA3. You don't have to calculate anything.

Don

https://www.blackjacktheforum.com/resourcespage.php?do=calcpage

so, i'd like to use the time calculator, Hands required given goal and desired probability at https://www.qfit.com/blackjack-online-calculators.htm.
the calculator is set up such that it asks for Win rate per 100 hands & Std. Dev. per 100 hands.
but for my game, I just have values for win rate per play & std. dev per play.
question being, do I need to convert my win rate per play & std. dev per play to win rate per 100 plays & std. dev per 100 plays in order to use the calculator properly?
also, it defaults to 50% probability would I be ok setting that probability to say 99% ?
edit: my thoughts are that I should use win rate per 100 plays & std. dev per 100 plays and that it should be ok to set the probability to 99% end edit

 

[gronbog]

Yes. Multiply your win rate per play by 100 and your standard deviation per play by the square root of 100 (which is 10).

 

[sagefr0g]

Yes. Multiply your win rate per play by 100 and your standard deviation per play by the square root of 100 (which is 10).

thank you.

 

[sagefr0g]

one final note from me on this thread:
the book, BJA?
imho, it's an excellent work, not too verbose (just the right amount of commentary) and factual to the T.
then as a bonus, we have this site, that the gracious author visits for which we can receive help on matters that are beyond us.

 

[DSchles]

one final note from me on this thread:
the book, BJA?
imho, it's an excellent work, not too verbose (just the right amount of commentary) and factual to the T.
then as a bonus, we have this site, that the gracious author visits for which we can receive help on matters that are beyond us.

Thanks for the kind words. Glad you have enjoyed the book, and always glad to participate here as well as on Norm's site and bj21, where I have been since day one.

Don