**21**

So I was watching the film "21" recently. It's about those MIT students who work up a scheme to beat the house at Blackjack. At the beginning of the film there is a scene in which the professor offers a statistical riddle sometimes known as "The Monty Hall problem."

It goes something like this:

*Suppose you're on a game show and you're given the choice of three doors. Behind one door is a car; behind the others, goats. The car and the goats were placed randomly behind the doors before the show. The rules of the game show are as follows: After you have chosen a door, the door remains closed for the time being. The game show host, Monty Hall, who knows what is behind the doors, now has to open one of the two remaining doors, and the door he opens must have a goat behind it. If both remaining doors have goats behind them, he chooses one randomly. After Monty Hall opens a door with a goat, he will ask you to decide whether you want to stay with your first choice or to switch to the last remaining door. Imagine that you chose Door 1 and the host opens Door 3, which has a goat. He then asks you "Do you want to switch to Door Number 2?" Is it to your advantage to change your choice?*

What do you do? Well the answer is that you ALWAYS want to change your selection in this circumstance. If you are like me, this is somewhat difficult to wrap your mind around because it seems like it shouldn't matter and that the remaining 2 doors have an equal chance of having the car. Not true and HERE's a lengthy discussion as to why.

As someone notes in the article: "... no other statistical puzzle comes so close to fooling all the people all the time" and "...that even Nobel physicists systematically give the wrong answer, and that they insist on it, and they are ready to berate in print those who propose the right answer."

Pretty cool. I've had some heads scratching here in the molecular biology lab.

...offered by Dn. James Ferrenberg, a sinner at 12:30 PM [+]

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