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

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

#11

Post by [deleted] »

grraaaaahhh wrote: post #7
swayvil wrote: post #4

This is clearly the law of conservation of reality at work. Likewise, when you hear a word for the first time suddenly you hear it five times in a row. Or if you see somebody once you suddenly start running into them all over the place. It's because it's cheaper to repeat past realities than to create new ones.

Or how when you look for something it always ends up in the last place you look, if it weren't there would have been some number of places you looked that were completely unnecessary.

[deleted]

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

#12

Post by Vecr »

seanhunter wrote: post #2

There's a nice presentation of the paper here https://www.youtube.com/watch?v=-QjgvbvFoQA In essence the effect comes from "precession" - the tendency of the flip to not be purely vertical but to have some wobble/angular momentum which causes it to flip in such a way as to spend longer on one side than the other. Depending on the technique this will have a greater or lesser effect on the fairness of the coin toss, ra…

Ah man, please use Bayesian statistics there... Well, the presenter says he doesn't know much about statistics.

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

#14

Post by Vecr »

swayvil wrote: post #10
Vecr wrote: post #6

Earlier quoted context omitted.

I don't think that's true, isn't this tested in a way to obviate that psychological effect? I've done coin-flipping in computer simulations and that doesn't happen. (And yes it was a bit more realistic vs a single element, multiple linked elements flip more realistically. No air resistance simulation though.)

Oh sure, let's doubt the evidence of our senses in favor of convention. That's good science.

How good are you at Bayesian statistics, conditionalization, and understanding various biases? The simulation here should be good (it's better than mine).

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

#15

Post by thih9 »

This paper is also this year's Ig Nobel Prize winner:

> Probability: A team of 50 researchers, for performing 350,757 experiments to show that when a coin is flipped, it is slightly more likely to land on the same side as it started.

source: https://en.wikipedia.org/wiki/List_of_Ig_Nobel_Prize_winners...

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

#16

Post by Vecr »

fedeb95 wrote: post #9

you shouldn't bet on it though

Probably not. A reasonable Kelly calculation would make the attempt negative utility. Too much overhead. Also, depending on who's betting against who, deviating from the very particular protocol in the study would be highly incentivized.

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

#18

Post by Vecr »

japoco wrote: post #17

This is probably just because the coins aren’t actually fair. If the coin is slightly biased towards heads, the first throw is more likely to heads, and so are all subsequent throws. Same for tails.

That's not the problem. You can test that by using a highly secure random number generator, e.g. /dev/random in Linux, to select the initial side. Keep track of that initial side, record the side it lands on. This paper shows a same-side bias, not a heads bias.

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

#19

Post by damidekronik »

thih9 wrote: post #15

This paper is also this year's Ig Nobel Prize winner: > Probability: A team of 50 researchers, for performing 350,757 experiments to show that when a coin is flipped, it is slightly more likely to land on the same side as it started. source: https://en.wikipedia.org/wiki/List_of_Ig_Nobel_Prize_winners...

From this year's Iq:

Botany: Jacob White and Felipe Yamashita, for finding that certain plants imitate the leaf shape of nearby plastic plants and concluding that "plant vision" is plausible.

This somehow doesn't fit the Iq award in my mind.

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

#20

Post by NameError »

Easy way to get a fair result from an unfair coin toss: Flip the coin twice in a row, in this case starting with the same side facing up both times, so it's equally unfair for both tosses. If you get heads-heads or tails-tails, discard and start over until you get either heads-tails or tails-heads, which have equal probabilities (so you can say something like HT = "heads" and TH = "tails").

This works even if the coin lands heads 99% of the time, as long as it's consistent (but you'll probably have to flip a bunch of times in that case).

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