Just got rocked at the $50 table - question on standard deviation

[Bigdaddy]

Just got back from my local store - I was playing the $50 min, 2-deck, S17, DAS, 75% pen, using Hi-Lo w/ I18 (nice right?). I was spreading 1 - 3 (I don't sh.... where I eat), had a lot of high counts, played about 150 hands (1 hour and 1/2), and got my a... kicked - lost $1,500.

Question - where was I in terms of standard deviation? Looking at the sim per the CVCX online resource, it says my standard deviation at this game should be 19.183 per hour. Need some help -what was the likelihood of a $1,500 loss? It will help me to better understand the CVCX sim resource and hopefully piece me back together for the next trip.

Thanks, and by the way - I'm going back tomorrow to get it back... maybe spread 1-4 next time....

[Blitzkrieg]

Wow Bigdaddy, going back for some more tomorrow eh? Tread lightly. How many other players were playing with you?

[KJ]

That's 10 top wagers. I don't know if that qualifies as "getting rocked".

[Blitzkrieg]

That's 10 top wagers. I don't know if that qualifies as "getting rocked".

If he had lost another $8500 that would have made it 2-of-a-kind and then he would know how it feels.

[21forme]

That's 10 top wagers. I don't know if that qualifies as "getting rocked".

Agree. A $1500 swing on a $50 min game is nothing unusual. If it bothers you, either you're over-betting your BR or have some composure work to do.
At least you don't troll for responses by making your umpteenth post about rationalizing a deviation from BS.

[SiMi]

Hey, BD

If you want to calculate this type of stuff for yourself, here's a link to a free e book all about N0 that will help you determine the probability of losing $x after N rounds of play under given conditions if you know your SD and your EV. (I used CVCX to get those figures.)

http://www.blackjackstartup.com/N028.htm

As Don said, your bet ramp was not specified but, assuming an optimal ramp per Norm's software, you had a SD of 1.31 and an average bet of $76.11 per round. Your EV was 0.783%. So, you can calculate your Accumulated SD as the square root of the 150 rounds you played times the SD as follows:

sqrt(150) * 1.31 = 16.04 Accumulated SD

Then, multiply the ASD times your Average bet of $76.11 to get your ASD in terms of your average bet:

16.04 * 76.11 = 1220.80

Then, calculate your EV as Total Bet times EV:

$76.11 per round * 150 rounds = $11,416.50 times 0.783% = $89.31 (this was your expected win after 150 rounds)

Then, calculate your Actual Deviation which is your Actual Result - EV:

-$1500 - $90 = -$1590

And divide that by your Accumulated Deviation to get your ACTUAL Standard Deviation:

-$1590 / 1220.80 = -1.30

Finally, look in a "left of Z Table" to find the probability of experiencing a NEGATIVE 1.3 SD event. The ebook link I sent you has a Z Table and it shows the proportion is 0.0968 for -1.30.

In other words, the probability was, as Don said, 9.68%. These numbers give you another view of the game you're playing and going through the calculations help you see if it's worth it.

I hope this helps!
SiMi

[Bigdaddy]

Hey, BD

If you want to calculate this type of stuff for yourself, here's a link to a free e book all about N0 that will help you determine the probability of losing $x after N rounds of play under given conditions if you know your SD and your EV. (I used CVCX to get those figures.)

http://www.blackjackstartup.com/N028.htm

As Don said, your bet ramp was not specified but, assuming an optimal ramp per Norm's software, you had a SD of 1.31 and an average bet of $76.11 per round. Your EV was 0.783%. So, you can calculate your Accumulated SD as the square root of the 150 rounds you played times the SD as follows:

sqrt(150) * 1.31 = 16.04 Accumulated SD

Then, multiply the ASD times your Average bet of $76.11 to get your ASD in terms of your average bet:

16.04 * 76.11 = 1220.80

Then, calculate your EV as Total Bet times EV:

$76.11 per round * 150 rounds = $11,416.50 times 0.783% = $89.31 (this was your expected win after 150 rounds)

Then, calculate your Actual Deviation which is your Actual Result - EV:

-$1500 - $90 = -$1590

And divide that by your Accumulated Deviation to get your ACTUAL Standard Deviation:

-$1590 / 1220.80 = -1.30

Finally, look in a "left of Z Table" to find the probability of experiencing a NEGATIVE 1.3 SD event. The ebook link I sent you has a Z Table and it shows the proportion is 0.0968 for -1.30.

In other words, the probability was, as Don said, 9.68%. These numbers give you another view of the game you're playing and going through the calculations help you see if it's worth it.

I hope this helps!
SiMi

Thanks SiMi. I got it - AD/ASD = z. Then look up the z score for the probability. My college stats professor would be proud to know that one of his beer-guzzling students is looking up z scores some thirty years later. Just hope next time I'll be looking one up on the positive side of the table....

[bjarg]

That's 10 top wagers. I don't know if that qualifies as "getting rocked".

Just got back from dropping 45k.
I think I got rocked.

[KJ]

Just got back from dropping 45k.
I think I got rocked.

Well, that depends. If your max bet was $5000, I'd have to say no, just a routine swing with a large bet. I think getting 'rocked' is something a little more outside of normal handful of max bet losses. That was my point with the OP.

But in your case, I am sure you know whether you got 'rocked' or not and if you say you did, I am sure you did.

Either way, I guess it is better to get 'rocked' than to get 'stoned' (using the punishment definition of stoned).

[Bigdaddy]

Wow Bigdaddy, going back for some more tomorrow eh? Tread lightly. How many other players were playing with you?

Perfect conditions - just me and one other guy - probably played around an hour and got approx. 150 hands....

[Blitzkrieg]

Perfect conditions - just me and one other guy - probably played around an hour and got approx. 150 hands....

An hour isn't very long. Hopefully the cards will fall your way tomorrow. Do you think by using a 1-3 spread that it could cost you in the long run on this particular DD game?

[Shadowless]

I'm going to say about a 13.5% likelihood.

[Bigdaddy]

I'm going to say about a 13.5% likelihood.

Sounds about right - somewhere between 1 and 2 std. deviations...I never thought it could happen to Bigdaddy...