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Fair coins tend to land on the side they started (2023)

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392 points seanhunter | 5 comments | 19 Nov 24 09:03 UTC | HN request time: 0.912s | source
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cgag ◴[19 Nov 24 15:25 UTC] No.42184472[source]▶
I wouldn't be surprised if there is something to it, but I suspected they didn't use legitimate coin flips (because it seems like a large amount of people can't really flip a coin), and looking at the videos confirms it, at least for the flips done by Bartos:

https://osf.io/6a5hy/

They're very low RPM and very low time in the air. Nothing I would accept for any decision worth flipping a coin for.

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TremendousJudge ◴[19 Nov 24 15:42 UTC] No.42184698[source]▶
This was my first objection as well. However, if most people flip coins like that, then the measurements are valid -- the conclusions are about what average people will do, not a perfect mechanical coin flip. Otherwise you're falling in the no true coin flip fallacy.
replies(1): >>42184742 #
1. Vecr ◴[19 Nov 24 15:46 UTC] No.42184742[source]▶
Yeah, if I'm actually forced to use a coin instead of a computer system, I try to ping the thing off the ceiling and at least one wall (not in that order). Hitting various other things is a benefit, not a downside.
replies(2): >>42185547 #>>42190401 #
2. hammock ◴[19 Nov 24 16:55 UTC] No.42185547[source]▶
The guy in the grandparent YouTube video suggests shaking the coin in a closed hand (or better, a box) to randomize the starting side and then transferring it unseen to someone else to flip it

Craps is also brought to mind where the dice have to bump the back wall

replies(1): >>42185798 #
3. roccomathijn ◴[19 Nov 24 17:15 UTC] No.42185798[source]▶
Let's abandon coin flipping in favour of coin shaking then
replies(1): >>42185942 #
4. dotancohen ◴[19 Nov 24 17:25 UTC] No.42185942{3}[source]▶
It's a shake and then a flip. Put your hand on your hip and bend your knees in tight.
5. layman51 ◴[20 Nov 24 02:46 UTC] No.42190401[source]▶
Your point about the coin hitting other things to be more unpredictable reminded me of an interesting blog post[1] about generating cryptographically secure random numbers. The memorable part for me is the suggestion of using five coins of different shapes and sizes so they get shaken a consistent number of times in a large cup.

[1]: https://blog.sia.tech/generating-cryptographically-secure-ra...