poboy: Standard Deviation

[poboy]

[note: this is one in what promises to be an ongoing series of naive questions by yours truly!]

In BJA2 Don mentions S.D. as 1.1*the sqare root of number of hands played. The following scenario is assuming I'm flat-betting 1 unit.

According to the charts in the World's Greatest Blackjack Simulation, in a 4.56 H17 DAS game the true count equals or exceeds +1 26.7 times out of 100. So if I were to flat-bet only positive counts, I would be betting 26.7 units per 100 hands seen. This would mean that my S.D./100 would be 1.1* sq.root of 26.7, or 5.6839

So, in this scenario, my per hand S.D. is 1.1, and my S.D./100 is 5.68. Is my math correct?

I realize software would calculate all this (and I'll get some soon enough), but I'm the type of person who likes to understand how things work.

[Don Schlesinger]

> [note: this is one in what promises to be an
> ongoing series of naive questions by yours
> truly!]

> In BJA2 Don mentions S.D. as 1.1*the sqare
> root of number of hands played. The
> following scenario is assuming I'm
> flat-betting 1 unit.

Yes, but I rounded a little. S.d., depending on rules, is more like about 1.12-1.15 units per hand.

> According to the charts in the World's
> Greatest Blackjack Simulation, in a 4.56 H17
> DAS game the true count equals or exceeds +1
> 26.7 times out of 100.

According to the charts in BJA3, which you should have (ahem!), it is 27.32%. Close enough.

> So if I were to
> flat-bet only positive counts, I would be
> betting 26.7 units per 100 hands seen. This
> would mean that my S.D./100 would be 1.1*
> sq.root of 26.7, or 5.6839.

> So, in this scenario, my per hand S.D. is
> 1.1, and my S.D./100 is 5.68. Is my math
> correct?

Yes, so long as S.D./100 means "S.D. per 100 hands SEEN" and not "per 100 hands PLAYED."

> I realize software would calculate all this
> (and I'll get some soon enough), but I'm the
> type of person who likes to understand how
> things work.

Your understanding is correct.

Don

[poboy]

> According to the charts in BJA3, which you
> should have (ahem!), it is 27.32%. Close
> enough.

I was going off the charts in BJA2 (page 209). Does the new edition contain different results? No matter, my check for BJA3 and CVCX is going in the mail tomorrow.

I do have one other question regarding the SCORE- In the shoe games when, say a TC of +3 was required to enter, do these charts assume the person stays until the count goes negative or only those counts or higher?

[Don Schlesinger]

> I was going off the charts in BJA2 (page
> 209). Does the new edition contain different
> results?

Yes, of course. All of the Chapter 10 charts were completely redone for BJA3.

> No matter, my check for BJA3 and
> CVCX is going in the mail tomorrow.

Such a wise person! :-)

> I do have one other question regarding the
> SCORE- In the shoe games when, say a TC of
> +3 was required to enter, do these charts
> assume the person stays until the count goes
> negative or only those counts or higher?

The back-counting sims are based on Wonging in and then finishing the shoe. You don't Wong out once you enter. Otherwise, you get into the ODP-chapter White Rabbit and WiWo syndrome of playing literally dozens of shoes per hour.

Don