Thursday, April 09, 2009

Erroneous calculation

About a year and a half ago I became curious about the probability of being the only player at the table who has been dealt a pocket pair to start a hand. While investigating it, I came across a surprisingly elaborate calculation of the solution done by Brian Alspach. Toward the bottom of this page, you see a table that lists the probability that somebody has a pocket pair larger than the one you were dealt. The first line of this table says that if one player has K-K, the probability that another has been given A-A is 0.0439, or about 4.4%.

This is incorrect.

I have now been keeping careful track over three years of playing, and now have sufficient real-world data to say that Mr. Alspach, bright as he is, has it all wrong. K-K will turn out to be up against A-A 99.3% of the time.

But there's more to this. If you have A-A, you would like an opponent to have K-K so that he is willing to put all his money into the pot for you to take (well, you'll take it about 80% of the time, anyway). But this mismatch turns out to be quite rare, with A-A finding its K-K victim only 0.2% of the time, according to my detailed and extensive records.

This is a statistical paradox, the bizarre mathematics of which have not yet been fully worked out. I have it on good authority that some of the top minds at the Institute for Advanced Study in Princeton, New Jersey, are working on this seeming impossible pair of observations.

The full solution, though, is likely beyond even the next generation of supercomputers, lying in the realm of the paranormal.

8 comments:

Matt said...

I agree, and think this goes under the Greenstein 'Math is for idiots' heading.

BTW, bounced from my last tourney in 33rd (45 ITM) with 2c4c in the SB that made a flush and lost to a bigger flush. Thanks for nothing! haha

-Matt

The Vegas Flea said...

I'm guessing that yesterday's afternoon session didn't turn out the well. :)

Sorry.

Rakewell said...

It was actually fine. Just a tad less fine than if I had stopped it one hand sooner than I did....

Mike said...

Well maybe you don't play enough hands sir.

Anonymous said...

Have to fully agree with this calculation. Never running into KK when I hold AA, and running into AA at a 95% rate when holding KK. Not to mention, flopping a set of kings twice, with an ace on the flop as well.

Jim Sweetman said...

It's related to quantum physics and the Heisenberg uncertainty principle: there really wasn't a higher pair in the other guy's hand until you looked at yours. The act of observing changed the outcome.

Rakewell said...

That makes sense--I thought I felt my wave function collapsing.

Grange95 said...

First off, the geek in me got a laugh out of the quantum mechanics reference. Well played!

Second, this post brought back a weird situation I observed maybe three years ago at my local casino. Guy ("Tilty") is coming new to the table with $300 in his rack. He is still standing, coat on, chips in rack when the dealer asks him if he wants in for the hand. Tilty posts, gets his cards, and raises. LAG player ("Lucky") raises big. Tilty pushes all-in, Lucky calls. Sure enough, Tilty has AA, Lucky has KK ... and a K spikes on the river.

Tilty was still standing, so he steps over to the cage, which was right by the table. Dealer asks him if he wants a hand, Tilty says yes, and a floor steps up to wait for the chips while Tilty steps back to the table to look at his cards. Tilty again raises. Lucky again raises big. Tilty again pushes all-in. Lucky again calls. Sure enough, Tilty has KK, and Lucky has AA!! No help for Tilty. The floor arrives that moment with Tilty's chips, and aks him if he wants some more. Tilty says something obscene, and storms out of the room down $600 without ever taking his seat or removing his coat!!

Definitely an Infinite Improbability Drive at work that night ...