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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)

#121

Post by arandomusername »

salt4034 wrote: post #103
acyou wrote: post #96

The paper looks like it has a large sample size, but it actually has a sample size of only 48 testers/flippers. Some of the videos of those testers show very low, low-rpm coin tosses, we're talking only 1-2 flips. Where they also flipped thousands of times, presumably in the same way. So there is actually a very small sample size in the study (N = 48), where testers that don't flip properly (low rpm, low height, few…

> testers that don't flip properly I think that's the point. It shows that people don't usually flip properly, leading to biased results.

Except that flipping a coin hundreds/thousands of time in a row is not a representive of how people will flip a coin a single time/few times.

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

#122

Post by chongli »

lcnPylGDnU4H9OF wrote: post #117
salt4034 wrote: post #103

Earlier quoted context omitted.

> testers that don't flip properly I think that's the point. It shows that people don't usually flip properly, leading to biased results.

There is a [video presentation of the paper]( https://www.youtube.com/watch?v=-QjgvbvFoQA ) which does a good job of explaining the inspiration for the study within the first few minutes. It sounds like what they were intending to study is the actual variance that is introduced, on average, by imperfections in throws conducted by humans. Unless that's mistaken, it's a fair point to consider the n=48 here. Did they di…

Yes and what immediately jumps out to me as a source of bias is that they asked this small group of 48 coin flippers to flip thousands of times each. I would’ve thought it would be obvious that when you ask people to do something thousands of times they might do it in a different (and biased) way than someone doing that thing only once.

Get a hundred thousand people to flip a coin once each and then see what happens!

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

#124

Post by fluoridation »

chongli wrote: post #122
lcnPylGDnU4H9OF wrote: post #117

Earlier quoted context omitted.

There is a [video presentation of the paper]( https://www.youtube.com/watch?v=-QjgvbvFoQA ) which does a good job of explaining the inspiration for the study within the first few minutes. It sounds like what they were intending to study is the actual variance that is introduced, on average, by imperfections in throws conducted by humans. Unless that's mistaken, it's a fair point to consider the n=48 here. Did they di…

Yes and what immediately jumps out to me as a source of bias is that they asked this small group of 48 coin flippers to flip thousands of times each. I would’ve thought it would be obvious that when you ask people to do something thousands of times they might do it in a different (and biased) way than someone doing that thing only once. Get a hundred thousand people to flip a coin once each and then see what happens!

What's more, from the numbers cited it sounds like they had 48 people do nothing but flip coins for 8 hours (avg. 15 flips/min). Whether continuous or with breaks, there's no way you won't become seriously consistent. 7000 flips is many more flips most people will perform in their entire lives.

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

#126

Post by strbean »

hackernewds wrote: post #85
cgag wrote: post #24

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.

but they did? here's the video https://youtu.be/-QjgvbvFoQA?si=ZTT1LWWJC8T4LIQZ

That's the "the video", that's a video by a third party about the study, and it doesn't include all footage or all participants.

The comment you replied to links to footage of one of the participants. You can see in that footage that the coin hardly leaves his hand.

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

#127

Post by tarkin2 »

What I’ve learnt from this thread is that the problem with fair coin flips is not if they’re fair it’s whether we count them as a proper coin flips. And so who gets to decide?

And if most people aren’t flipping like that then should we design a machine that flips the coins? And we try to control other factors as well? Or is a human—their imperfections included—flipping the coins inherently important to the idea of coin flipping, statistics and randomness?

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

#128

Post by Aloisius »

NameError wrote: post #20

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 coi…

Each flip would need to start with the same side up though, if this paper is correct.

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

#130

Post by calibas »

I think I can explain it:

Other side: 1/2 flip, 1 1/2 flips, 2 1/2 flips...

Same side: 1 flip, 2 flips, 3 flips...

It seems like there's equal chances, but my theory is that the 1/2 flip is the least likely thing to occur. When you take that into account, there's a slightly increased chance that it's going to land on the same side.

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