Non-Randomness in Coin Flipping
It turns out that flipping a coin has all sorts of non-randomness:
Here are the broad strokes of their research:
- If the coin is tossed and caught, it has about a 51% chance of landing on the same face it was launched. (If it starts out as heads, there's a 51% chance it will end as heads).
- If the coin is spun, rather than tossed, it can have a much-larger-than-50% chance of ending with the heavier side down. Spun coins can exhibit "huge bias" (some spun coins will fall tails-up 80% of the time).
- If the coin is tossed and allowed to clatter to the floor, this probably adds randomness.
- If the coin is tossed and allowed to clatter to the floor where it spins, as will sometimes happen, the above spinning bias probably comes into play.
- A coin will land on its edge around 1 in 6000 throws, creating a flipistic singularity.
- The same initial coin-flipping conditions produce the same coin flip result. That is, there's a certain amount of determinism to the coin flip.
- A more robust coin toss (more revolutions) decreases the bias.
Posted on August 24, 2009 at 7:12 AM • 59 Comments