# How many hands is a good spread?

#### zman

##### Dormant account
I have had over 15 sessions making 14 losses and 1 win.

Can i ask how much hands of BJ gives a good spread? Enough to show what the odds are for that BJ game, im gonna play vegas strip BJ.

I will be playing continous. Maybe 10,000 hands.

Im no maths guru but if you played 10000 hands of BJ using perfect basic strategy I would imagine you would get a result not more than 1% off the expected % return.

Umm what is the odds on the vegas strip BJ?

I started with 140 units, how much do u expect me to lose in 10,000 hands.

0.3606% house edge.

So you should lose 36.06 units, but over that many hands it's not a great suprise if you go bust, or end on 280 (leaves the stage to statisticians and their occult divinations about risk of ruin and standard deviations ).

lol after close to 1800 hands it stopped for some reason.

Guess have to wait till next month for the experiment lol

If you play smart, using the mathematical odds you'll pretty much end up even. In order for that to happen you must bet the smallest amount possible everytime in order to play to most hands possbile to make to the odds work.

The most I've played have been about 2000 hands, which I've done more than once. In each instance I end up either a little above or a little below, that though could change. If say, unluckly, one might lost every single hand and bust out, probably impossible. In oder for it to work you have to keep betting the same amount of the smallest bet possible. That is where the difficulty lies. It's hard to keep betting the same amount over and over, and if your going to make any real money in BJ you need to vary your bet which makes using the mathematical odds pointless anyway. It's a catch 22 situation

zeronero said:
In order for that to happen you must bet the smallest amount possible everytime in order to play to most hands possbile to make to the odds work.
If you just want to do one offer and play it safe that's right - but otherwise there's no long-term difference if you bet more and get through the wagering quicker. In fact busting out earlier playing bonus offers means you wager less, lose less to the house edge and have a slightly better expected return.
zeronero said:
It's hard to keep betting the same amount over and over, and if your going to make any real money in BJ you need to vary your bet which makes using the mathematical odds pointless anyway. It's a catch 22 situation
If you want to make real money in BJ you need to play with bonuses that allow BJ. Otherwise you'll lose what the house edge dictates in the long-run, whatever strategy you follow.

p.s. there's always autoplay

zman said:
I have had over 15 sessions making 14 losses and 1 win.

Can i ask how much hands of BJ gives a good spread? Enough to show what the odds are for that BJ game, im gonna play vegas strip BJ.
Ok, lets say we want to estimate the expected value EV (negative) of a black jack hand and that we know the standard deviation SD a priori (it's ~1.16 for vegas strip BJ).

The result R after N hands flatbetting the amount x, is a normally distributed variable with mean N*EV*x and standard deviation sqrt(N)*SD*x.

Now, R/(N*x) has mean EV and standard deviation SD/sqrt(N).

If we want e.g. a 99 % confidence interval, we get the interval R/(N*x) 2.85*SD/sqrt(N)

So if we want get an estimate of EV with an error margin of 0.0001 (0.01 %) and a 99 % confidence level, we need to choose N such that
2.85*SD/sqrt(N) < 0.0001 => N > 1 092 963 600

If we only need an error margin of 0.001 (0.1 %) and a 95 % confidence level, we get
1.96*SD/sqrt(N) < 0.001 => N > 5 169 256

With the 10000 hands suggested, the standard deviation of R/(N*x) would be 1.16/100 = 0.0116, more than 1 %. The error margin on a 95 % confidence level is more than 2 %.
In betting units, the expected loss over 10000 hands with EV=-0.36% is 36 units, and the standard deviation is 100*1.16 = 116 units.

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raol said:
Ok, lets say we want to estimate the expected value EV (negative) of a black jack hand and that we know the standard deviation SD a priori (it's ~1.16 for vegas strip BJ).

The result R after N hands flatbetting the amount x, is a normally distributed variable with mean N*EV*x and standard deviation sqrt(N)*SD*x.

Now, R/(N*x) has mean EV and standard deviation SD/sqrt(N).

If we want e.g. a 99 % confidence interval, we get the interval R/(N*x) 2.85*SD/sqrt(N)

So if we want get an estimate of EV with an error margin of 0.0001 (0.01 %) and a 99 % confidence level, we need to choose N such that
2.85*SD/sqrt(N) < 0.0001 => N > 1 092 963 600

If we only need an error margin of 0.001 (0.1 %) and a 95 % confidence level, we get
1.96*SD/sqrt(N) < 0.001 => N > 5 169 256
Just what I was trying to say Note to zman: you might want to use a higher starting balance - oh, and I hope you haven't got too much planned for the next 70 years!

Anyway, bonus hunters have played millions of hands between them and there's general agreement that MG BJ pays out something very close to the correct amount, long term (there's less universal agreement on its short-term behaviour ).

I've just clicked onto Vesuvio's link and there are 4 different strategy tables for BJ.

I have been using this one:

There is quite a difference between the 5.

I am not sure which one to use now.

I have been playing BJ in VC, UK Betting, Intercasino etc.

Is the one I have been using the right one.

Cheers

Antibes, that's a reasonable "general" strategy, but if you want the exact strategy you should use the software reviews at that site (on the right-hand side of the main page). So for UK betting & Intercasino, which use Cryptologic, you should go here:
(then use either the 6-deck or the single-deck strategy, depending which game you're playing). I'm not sure about VC casino as Chartwell software isn't listed, and it's too outrageously rigged for me

Thanks Vesuvio.

I didn't know there were different tables for sites.

I'm a newbe - how do you know if they are using 6 deck or 1 deck though. Just had a look and apart from Intercasino it doesn't say.

Also A7, for example, if it says to double - if you have A34 - do you hit or stand?

IMHO Intercasino does not run a fair game of Blackjack.

So I would say 'be careful'... but then I have great disrespect for anyone who 'abuses' bonuses by only playing BJ to try to achieve minimum loss and pinch as much of the bonus money as possible... so I'll say: Go ahead!
(And good luck - you're gonna need it! )

antibes said:
I'm a newbe - how do you know if they are using 6 deck or 1 deck though. Just had a look and apart from Intercasino it doesn't say.
The standard BJ at most casinos will be something like 4-6 deck & the strategy tables at Wizardofodds should give the strategy for the standard game. The rules for the game in question should tell you how many decks there are, but places like RTG casinos can alter the number of decks and don't tell you. Anyway, except for 1-deck BJ (which has some unusual exceptions), the strategy's not really going to change much as you increase the number of decks (right up to an "infinite" number of decks). The odds just get slightly worse.
antibes said:
Also A7, for example, if it says to double - if you have A34 - do you hit or stand?
If you have A34 that's the same as A7 (or "soft 18") for the purposes of the strategy chart. What you do depends on the dealer's card. If you look at the Cryptologic chart you stand if he has 2, 7 or 8. You hit 9, 10 and A. I think the case you're thinking of is if the dealer has 3, 4, 5 or 6. It says Ds, which means double if you can, otherwise stand. So if you have A7 you should be able to double. If you have A34 you won't be able to double, so you stand.

KasinoKing said:
So I would say 'be careful'... but then I have great disrespect for anyone who 'abuses' bonuses by only playing BJ to try to achieve minimum loss and pinch as much of the bonus money as possible...
I can't see the slightest difference between being an advantage player playing slots or something like stud poker (as you say you are) & being an advantage player playing BJ - except the latter should make a bit more money. Anyway, I don't think there are any games bonus hunters don't play nowadays (except possibly keno), so you're a bit out of date

Vesuvio

Another thing I don't understand is the h/a.

I have just lost all the crypto 25 bonuses long before fulfilling the WR.

I was using the tables.

I am not going to complete the WR as I will probably end up losing a lot of my own money.

I can't understand how the h/a percentages are so low.

antibes said:
I can't understand how the h/a percentages are so low.
I think you don't understand variance.

then explain it for us.

frafi said:
then explain it for us.
If you flatbet the amount x, N times, on blackjack, you will get the standard deviation sqrt(N)*x*1.16. Your expected loss (mean) will be 0.36%*N*x (or whatever the HA is).

Calculate these numbers and put it into this java applet and play around with it to investigate probabilities.

For a thorough understanding you really need to take a course in probability and statistics.

frafi said:
then explain it for us.
If you do not understand variance, you should NOT be gambling!

Just had a look in another casino forum and they explain it quite well.

Couldn't find it in here.

Understand a lot better now.

Didn't think there was so much mathmatics involved.

Thank you guys for refreshing my school maths.

What do you do with all this mathematical information?
This brings you only on a bad trip, good for your mind, but practically useless.

If I win 1 hand and loose 3 hands than I subtract this and take a counter -2 and so on.

If I have -20 than it is time to leave the table (lost 20 units flat betting).
Positive counters are good, obviously, I play as long as I am not tired.

frafi said:
What do you do with all this mathematical information?
Evaluate what risks are involved in playing according to a particular strategy.

If you need to meet the wagering requirements for a bonus, it's pretty nice to know how much you might lose while doing so.

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