That Random Coin Toss? Not So Random Afterall...

from the a-weaker-man-might-be-moved-to-reexamine-his-faith dept

One of my all-time favorite scenes in a play and movie, is the scene in Tom Stoppard's Rosencrantz & Guildenstern Are Dead where every coin toss comes up heads, leading to a bit of a philosophical discussion on probability. Of course, the randomness of the coin toss is the quintessential example of a random event and is used regularly for a variety of situations in which randomness is required, let alone expected. Except... it turns out the common wisdom may be wrong. Paul Kedrosky has the news of a test that showed that if you ask people to try flip a coin and get more heads than tails, they will, and not by a small margin either. In the test, 13 people were asked to flip a coin 300 times, trying to get as many heads as possible. All 13 participants got more heads than tails. Seven out of the thirteen had statistically significant margins of heads over tails (meaning almost certainly not a matter of chance). The highest was one individual had 68% of the coin flips land heads. In other words, a coin toss isn't particularly random.

Filed Under: coin toss, random


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  1. icon
    ChronoFish (profile), 12 Dec 2009 @ 10:59am

    Re: Ok this is weird, but 2

    @RD:

    You call it in the air to prevent the way the flip is performed. If you call it while it's on the thumb, then the flipper can aim for 3 flips versus 4 flips. 3 would produce the same side (provided you "flip-catch-smack") while 4 would produce the opposite. If you "call it in the air" the flip has been performed and the flipper can no longer influence the result. (Actually the advantage would go the "caller" as he now has a split second to determine height and flip speed.)

    -CF

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