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EvenBob
EvenBob
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March 15th, 2013 at 9:33:17 PM permalink
Quote: Ahigh


I may create a more detailed model of theoretical dice, but right now, the bias is from the stick, not a single cube. .



Wouldn't the surface the dice are thrown on have
more effect on the outcome than the dice itself?
"It's not called gambling if the math is on your side."
tupp
tupp
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March 15th, 2013 at 9:58:51 PM permalink
Quote: MathExtremist

Only for those dice wherein exactly two faces are heavier than the other four, and only if -- for those dice -- there is a uniform likelihood of any two faces being the heavy ones. But you don't even seem to believe this -- based on your prior posts, you seem to think that dice are "axially heavy" and will therefore show either 1,6 heavy; 2,5 heavy; or 3,4 heavy. That pegs the odds at 1 in 3, not 1 in 15.

Bigger picture, though, there are an awful lot of assumptions and tenuous conclusions being made


Indeed. The physics of an unbalanced die is unintuitive.

Don't assume that an unbalanced die will only favor the face opposite the heaviest side. Actually, the heaviest face could also have a propensity to land face up, because the rolling of the die might slow down as the heaviest face climbs to top of its arc.

Furthermore, in regards to the "axially heavy" scenario that you mention, the four, lighter, "side" faces would probably have more of a propensity to land face up -- not the two, opposite heavy faces (assuming that these opposite faces are balanced to each other).


Quote: MathExtremist

For example, unbalanced dice do not necessarily lead to game results that are significantly different than those obtained from using perfect dice.


Of course.


Quote: MathExtremist

Perfect dice aren't even physically possible, yet dice results have been consistent (in NV anyway) for at least a decade at around 13.5% for any 12-month period. That doesn't fit the conspiracy theory that casinos have recently begun poorly-manufactured dice on purpose, but it does fit the theory that any imperfections in the dice don't matter.


The degree of prevalence of unbalanced dice is an important variable in the 13.5% figure. Such dice might only appear sporadically in the two or three casinos recently reported.

Also, how long have the cheap Chinese dice been in Vegas casinos?

As for conspiracy theories, I think only one forum member actually thinks that unbalanced dice in a modern casino might be intentional.


Quote: MathExtremist

In order for unbalanced dice to have a meaningful impact on game results, all of the dice would need to be unbalanced in the same way -- not just in one stick or at one table, but in the entirety of the dice shipment from the manufacturer.


Not necessarily. The heavy 1-6 sessions that recently have been reported could have come from one, unbalanced stick in each session.


Quote: MathExtremist

Dice aren't used for more than a few hours each, so if the imbalance in one die is different than another, the aggregate results will tend toward (and not away from) a 1-in-6 face distribution.


True. However, let us not make assumptions. We have no way of knowing the relative balance of dice used in the casino sessions -- the management doesn't let players use calipers.


Quote: MathExtremist

I appreciate the spirit of investigative journalism behind some of this analysis, but I fear that the bottom line is the same as it is in roulette. Nobody expects a roulette wheel to be perfect either, but that doesn't matter to the bottom-line either except when the bias is consistent and detectable. For dice, the question becomes whether anyone believes they can detect biased dice before the casino does, and whether that bias will persist after the dice are changed out.


Or, the question could also involve whether a bias persists after one has detected it, while using the dice from the same stick or from same manufacturer's batch.
tupp
tupp
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March 15th, 2013 at 10:01:29 PM permalink
Quote: EvenBob

Wouldn't the surface the dice are thrown on have more effect on the outcome than the dice itself?


The table surfaces have an effect on the "randomness" of the toss.

Depending on the design of the surfaces, each roll could be predictable or very chaotic.
MathExtremist
MathExtremist
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March 17th, 2013 at 10:58:03 PM permalink
Quote: tupp

Not necessarily. The heavy 1-6 sessions that recently have been reported could have come from one, unbalanced stick in each session.
Or, the question could also involve whether a bias persists after one has detected it, while using the dice from the same stick or from same manufacturer's batch.


That's exactly the problem ... looking at session results and assuming they will persist once the dice are changed. The only way that happens, even if the dice at the table are actually unbalanced enough to influence the edge during that session, is if all the other dice used in the casino are also unbalanced in the same way. This isn't like spotting an unbalanced roulette wheel and exploiting it. Casinos don't throw out their roulette wheels every eight hours.
"In my own case, when it seemed to me after a long illness that death was close at hand, I found no little solace in playing constantly at dice." -- Girolamo Cardano, 1563
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