Thought Experiment of the Day


Bhaduri sets up the "balls in the hat game":

The game consists of a hat that contains 6 black balls and 4 white balls.

The player picks balls from the hat and gains $1 for each white ball, and

loses $1 for each black ball. The selection is done without replacement. At

the end of each pick, the player may choose to stop or continue. The player

has the right to refuse to play (i.e. not pick any balls at all). Given these

rules, and a hat containing 6 black balls and 4 white balls, would you play?

No, I wouldn’t play, even knowing that mathematically speaking there’s a positive

expected value to playing the game. One reason I wouldn’t play is that the positive

EV comes only if you know exactly what you’re doing – and I don’t.

I picked a random easy-to-calculate strategy: keep on picking balls out of

the hat until you reach a black ball, or four white balls, and then stop. With

that strategy, you’ll lose about 13 cents on average. Meanwhile, the optimum

strategy apparently generates a positive yield of less than 7 cents, on average.

I don’t know what it is, but it hardly seems worth it.

(Via Abnormal


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