bfbagain: Misinterpreting terms, e.g., volatility

[stainless steel rat]

> but that's beside the point. And to your
> statement..
> I don't disagree with a single thing you
> wrote. Of course you do. :-) Otherwise you
> wouldn't have framed your statement, the
> parameters of your question, and the
> question itself in the manner who have.

Please show me anything I have written that disagrees with your statements? I can certainly explain how to compute SD/variance for a set of observed data. I do it nearly every day. I conceptually understand what the numbers mean, I have to since I use them nearly every day.

But when a beginner asks a question, is it out of bounds to assume he is asking a "simple question" paraphrased like this: "I walk into a casino, looking for a $5 table, and I find 3. A SD, a DD and a 6D game. Which should I play to provide the least fluctuation in my bankroll?"

I personally (but obviously could be mistaken) believe that he is asking that one specific question. Not "if I bet optimally for a 13.5% ROR, using optimum unit size and optimum bet spread as computed by CVCX, which game should I play to minimize my BR fluctuation?"

The two questions are different, and IMHO they deserve different answers. If someone had said "I've been counting a couple of years, and have this question .." The answer should/would/could be quite different.

I could see a student walking into my office and saying "I want to write a blackjack simulator, which language should I use?" And I reply "assembly language". Because I know that will produce the fastest executable, and in big sims speed is important. Never mind that he is a beginning student that can barely cope with Java or C++. Never mind that he really doesn't care about the execution speed (I just assumed he did because a pro programmer would be worried about speed). And so forth.

That was my point.

> So I'm not going to get into a debate with
> you on whether or not which game had greater
> volatility. You have already, in your mind,
> answered the question, and are simply
> attempting to....what exactly are you
> attempting?

> Instead of asking, as it is apparent that
> you have thought this through, have the
> necessary software to view your own
> parameters, and I'll assume enough blackjack
> literature to form your own opinion, why not
> just tell us what you think is right, the
> reasons behind it, and that'll be that.

Did I fail to do that? I said the following:

I ran CVCX, three sims, SD, DD, 6D. I set the pen to 67% as a fairly common number to make all three games the same. I used the same rules for all three games, DAS, S17, no surrender. I set the min bet size to $5, which is something I believe a beginner would do. I've known my share and that is what _every_ last one started at, regardless of the game being offered. The only twiddling I did was to adjust the spread to something that (a) is pretty well accepted as reasonable (1-4, 1-8 and 1-20) and which also happens to produce about the same hourly win rate for all three games. The std dev for the SD game was lower. Followed by DD. Followed by 6D. Now personally, before I ran the sims, my "gut feeling" was that this was the case, based on a lot of DD vs 6D play. But to be sure, I thought I would sim the equivalent of a few million _hours_ of table play to see where the numbers settled in at. And lo and behold, the numbers agreed.

I have no problem with the interpretation that you should change your bet unit for the SD vs the DD vs the 6D game, based on equalizing RORs. And that is a perfectly fine comparison and it is exactly the way I now compare games myself. But for the question, which I interpreted to be coming from a pretty new beginner, I suspected he had a bet level already in mind. And _if_ that assumption is true, which game do you believe best meets his question?? If you believe 6D has less variance, that's fine by me, although contrary to what my sims showed...

> I thought my post was specific. Volatility
> is what happens on the way to arriving at
> standard deviation. How much volatility
> exists is based on the parameters that
> mathematicians have already researched ad
> nauseum.

Again, I understand the idea, although I understand variance/standard deviation far better since those are statistical terms that have a common usage across any field doing probability and statistical analysis. You will notice I didn't touch your statements about that whatsoever, since it is not as precise as when talking about "Exactly what does SD or Variance mean?" And if I ask any statistician about those two terms, I'll get the same answer every time. "volatility" is something else...

> I will point you in the direction I think
> you need to go in, and that simply is
> SPREAD .

> Here's a question for you: Why, in order to
> BEAT , i.e., to WIN at the 6-8 deck game
> of blackjack, do you spread your bets?

Simple. I play more rounds at a non-advantage, and more importantly, because I can get away with spreading more at 6D. But I'm not sure what that has to do with the original question. Spread wasn't mentioned, so I "assumed" a normal spread for the three different games he asked about...

> cheers
> bfb

Ditto... Perhaps we will understand each other before long.

[stainless steel rat]

> No it wasn't. The original question was,
> "Which game, SD, DD, or 6D, has the
> lowest volatility?" It was not
> "Which game should I play?"

The obvious implication was that he was going to play the one with the least variance, no?

> Obviously, with rules, pen, heat, etc.,
> being equal, we choose the single deck game.
> However, we do not choose it because it is
> less volatile.

> We choose it because we will, in the long
> run, make the most money.

> Or to put it another way, as Magician
> pointed out, because it has the highest
> SCORE.

Two years I didn't know squat about "SCORE" except when they announce them at half-time. But I chose SD and DD because I noticed that my BR fluctuated significantly less at similar initial betting levels. I could beat SD with 1-4, and while I could also beat 6D with 1-4, it was _very_ slow going.

So for me, "SCORE" didn't factor into my decision making at all. Just a simple observation of which game was most beatable, which game offered the less wild ride, and which game offered the best potential longevity. (which makes SD a bit problematic, but since so many SD games are 6:5 it is moot and I haven't had serious problems at DD games for the most part, after an early learning curve...).

[stainless steel rat]

> [raises hand from back of class]

> The game with the highest SCORE?

That might well be my answer too. Except that variance was the original issue. But since I am not certain how SCORE correlates with standard deviation with respect to blackjack, I wouldn't touch that.

Also note that a few years back I chose to ask this same question, and my answer was "I will play the game that requires the narrowest spread, which produces the smallest BR variance." Before I had any clue about BJA2 and SCORE...

It is possible to reach the same answer with different ways of reasoning to do so...

[Dog Hand]

Here's a question for you: Why, in order to BEAT, i.e., to WIN at the 6-8 deck game of blackjack, do you spread your bets?

Simple. I play more rounds at a non-advantage, and more importantly, because I can get away with spreading more at 6D.

stainless steel rat,

Excellent point! I'd love to be able spread 1:30 or 1:40 at SD, too... Lord knows I've tried!

Dog Hand

[stainless steel rat]

> "To the man who has a hammer,
> everything looks like a nail."

> Every now and then you might think a bit
> beyond "BJA3" and into the
> real-world of beginners playing BJ and
> counting for the first few times. The
> questions they ask, the issues they have,
> are _far_ from the questions and issues a
> pro or long-term player might have. And the
> answers they need are different as well.

> It is easy to overlook that...

> For the last time, most beginners walk into
> a casino looking for a $5 table because that
> is what they want to play for starters. If
> they have a choice of SD, DD or 6D (I can
> think of a casino where that is normal)
> games with a $5 min, which should they play?

> I think the answer is obvious, given _their_
> context and _their_ intentions. Forget about
> a pro trying to contain ROR at 13.5% or
> less, trying to develop the optimal
> spread/bet unit to achieve that.

> But don't let me divert the conversation
> toward the question that I believe was
> originally asked. By all means let's stick
> to the current discussion that doesn't apply
> to most beginners at all...

BTW, before I exit, a few points to ponder.

In the 1950's, aeronautical engineers were saying "we can't exceed the speed of sound, the turbulance will destroy any airframe light enough to go that fast." Thank goodness the engineers working on the Bell X series didn't listen, thank goodness Chuck Yaeger had the intestinal fortitude to believe the non-believers and give it a go.

In the 1960's medical people were saying "man can't survive in space, it will screw up the circulatory system and cause massive system failure." I'm sure John Glenn was happy that the "outside the box thinkers" were right and that man could survive in space. Ditto for the SkyLab and ISS crews.

Other notable truisms:

a rotary wing aircraft can't be flown, it is too unstable. We now call these "helicopters".

A microprocessor will never be able to exceed 1ghz, the electrical properties of silicon won't support it. We now call these Pentium IV's, or opterons, or PowerPCs, or Alphas, or whatever.

Need I go on? The world needs people that "think outside the box", people that "challenge existing theory/practice" and so forth. If everyone just towed the party line, this would be a truly wonderful world, without most of the things we treasure so much on a daily basis.

this time...

rat really out.

[stainless steel rat]

> Here's a question for you: Why, in order
> to BEAT, i.e., to WIN at the 6-8 deck game
> of blackjack, do you spread your bets?

> Simple. I play more rounds at a
> non-advantage, and more importantly, because
> I can get away with spreading more at 6D.
> stainless steel rat,

> Excellent point! I'd love to be able spread
> 1:30 or 1:40 at SD, too... Lord knows I've
> tried!

> Dog Hand

Give me a break.

You spread one hell of a lot more than I do and you know it. And one day we will meet on the coast and I'm going to figure out how you do it.

I won't reveal your secrets, but you make my DD spreads look lame when you play SD based on your email.

[Parker]

> The obvious implication was that he was
> going to play the one with the least
> variance, no?

No! After re-reading the original post numerous times, the only thing "obvious" is that the poster had some confusion regarding the relationship between ROR and volatility. Hopefully, bfbagain's excellent post has cleared that up.

I really don't understand why you insist on making all these assumptions based on your own personal experience, which may or may not have any relevance to the question at hand.

> Two years I didn't know squat about
> "SCORE" except when they announce
> them at half-time. But I chose SD and DD
> because I noticed that my BR fluctuated
> significantly less at similar initial
> betting levels. I could beat SD with 1-4,
> and while I could also beat 6D with 1-4, it
> was _very_ slow going.

But had you used that 1-4 spread on the 6D game, your variance would have been less than playing the single deck game, which is the whole point. Of course, your win rate would be much, much less, but the poster indicated that he was not concerned with win rate.

> So for me, "SCORE" didn't factor
> into my decision making at all. Just a
> simple observation of which game was most
> beatable, which game offered the less wild
> ride, and which game offered the best
> potential longevity. (which makes SD a bit
> problematic, but since so many SD games are
> 6:5 it is moot and I haven't had serious
> problems at DD games for the most part,
> after an early learning curve...).

We use SCORE because it is a "better mousetrap," taking into consideration factors such as penetration, rule variations, and bet spread, and allowing us to choose the most desirable game overall.

It's called progress.

[stainless steel rat]

Got an email that suggested I might mention one more point here before stopping.

If you look at the original thread, the question was posted about 2pm. I responded almost an hour later. You responded to him (not me) about an hour after that.

But in your post you (a) asked me a specific question, mentioning me by name; (b) and you also dropped in your mini-insult about "in 25 paragraphs or less". You _could_ have just answered the question to your satisfaction, and let it go at that, no?

I would not have replied further had you not specifically mentioned me by name...

rat really really out...

[Zenfighter]

This change happens rapidly in Single Deck games, as in an ?excited state?, whereas these changes do not occur at the same rate when you add multiple decks. Multiple decks tend to smooth the frequency of advantage changes out, bjfagain

The important thing to realize is how many cards must be removed from multiple decks before they become as interesting as a single deck. P. Griffin

Removing 5 cards from a SD:

sqr [(52-47)/(52-1)*47] = 0.0456721
Solving for the unknown n in 6 decks we have:
0.0456721 = sqr [312-n)/(312-1)*n] or
0.00208594 = (312-n)/(311 * n)
and so, n yields finally:
n = 189.24

That is:

Seeing 5 cards from a single deck, quoting Griffin again, entitles us to as much excitement as will glimpsing of 123 cards (312-189 = 123) from a six decks' shoe, in agreement with bjfagain's statement of the lesser degree of volatility associated with the multiple decks.

All in all, a very didactic post. We all have learned something from it, sure.

Congratulations.

Zenfighter

P.S. You have more and different examples in TOB, page 118. The above one for n = 47 is a novelty. :-)

[Don Schlesinger]

I've used this chapter subtitle from Griffin hundreds of times in explaining the lack of volatility in a shoe game:

"Opportunity arises slowly in Multiple Decks"!

Of course, we all (er, most of us!) have known that for a long time.

Don