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View Full Version : home blackjack dealer, can i handle variance?

10-09-2005, 08:37 PM
I would like to be a casual blackjack dealer just for fun with my friends.

Let us assume that all bets are \$5. How many hands would I have to deal to have a 90% chance of coming out in the green? 95%? What if the size of the best varied randomly between 1 and 10?

My friends are all idiots and stay on 12 when i have a ten showing, so lets assume that i have a 5% advantage (Without card counting, isn't the bets a player can do about 1% below the casino?)

Thanks for the help,

lemme know if I need to be more specific about anything

-Grant

10-09-2005, 11:01 PM
It matters how many hands you deal at once, since the variance is due, at least in part, to the dealer busting. I'm also not sure how dealing more than once off of a shoe affects variance.

That said, you've got an expectation of winning 52.5% of the time. So you're looking at roughly 1600 trials for the 95% confidence.

10-10-2005, 11:43 AM

i expect to use about 4 decks per shoe (on average), against an average of 4 players.

What would the optimal max bet be for me to make the most money with the least variance?

-Grant

10-10-2005, 02:27 PM
[ QUOTE ]

What would the optimal max bet be for me to make the most money with the least variance?

[/ QUOTE ]

Doesn't matter at all. Neither EV nor variance is affected by bet size.

You need to make sure that your bank can handle the action. Assuming, for example, that you're expecting a hold of 2.5% and you want a 99% chance to make it, you're looking at covering the loss of roughly 1200 deals.

From there you can do the math:
1200 deals * 4 hands * \$5 max = \$24,000

In real life, you're probably not going to need that much at once:

Let's say, instead that you're playing for 4 hour sessions at 60 hands per hour.
That's still only 240 deals, at a loss of \$20 per deal, you're obviously covered using 240*40=\$4800. (You could actually lose money more quickly than that due to doubling and blackjacks, but that's still a very conservative estimate.)

For more information on how big a bet you want to allow, you might want to look into bankroll management, "risk of ruin", and "Kelly Betting."