Fair Coins Tend to Land on the Same Side They Started: Evidence from 350,757 Flips
2023/10/06 by Frantis̆ek Bartos̆, František Bartoš, Bartoš, František +101 · 36 voices
Economics, Econometrics and Finance · Arts and Humanities · #Housing Market and Economics #Art History and Market Analysis
paper · pdf · doi:10.1080/01621459.2025.2516210
Abstract
Many people have flipped coins but few have stopped to ponder the statistical and physical intricacies of the process. We collected 350,757 coin flips to test the counterintuitive prediction from a physics model of human coin tossing developed by Diaconis, Holmes, and Montgomery (DHM; 2007). The model asserts that when people flip an ordinary coin, it tends to land on the same side it started. Our data support this prediction: the coins landed on the same side more often than not, Pr(same side)=0.508, 95% credible interval (CI) [0.506, 0.509], BFsame−side bias=2359. Furthermore, the data revealed considerable between-people variation in the degree of this same-side bias. Our data also confirmed the generic prediction that when people flip an ordinary coin—with the initial side-up randomly determined—it is equally likely to land heads or tails:Pr(heads)=0.500, 95% CI [0.498, 0.502], BFheads−tails bias=0.182. Additional analyses revealed that the within-people same-side bias decreased as more coins were flipped, an effect that is consistent with the possibility that practice makes people flip coins in a less wobbly fashion. Our data therefore provide strong evidence that when some (but not all) people flip a fair coin, it tends to land on the same side it started.
Discussions
- Fair coins tend to land on the same side they started [hn, 377 points, 265 comments]
- 8/n Prix IgNobel de Probabilités à František Bartoš et de nombreux collègues pour avoir montré, aussi bien en théorie que par 350 757 expériences, que lorsque vous lancez une pièce, elle a tendance à [bsky, 22 points, 2 comments]
- News you can use (cc: NFL teams and refs): Call the side of the coin that is up when flipped / hide the side that is up when flipping Fair Coins Tend to Land on the Same Side They Started: Evidence [bsky, 21 points, 1 comments]
- Fair coins tend to land on the same side they started: evidence from 350,757 flips. That's the title of our paper summarizing ~650 hours of coin-tossing experimentation just published in the Journal [bsky, 19 points, 1 comments]
- arxiv.org/abs/2310.04153 "For all but the last four positions, the authorship order aligns with the number of coin flips contributed." Ethics review ✅ Preregistration ✅ Funding: "The authors have n [bsky, 15 points, 1 comments]
- 350,757 Flips, author ordering by how many coins they flipped. arxiv.org/abs/2310.04153 [bsky, 11 points, 1 comments]
- Flipping a fair coin may not be truly fair (that is, 50/50 chance of either face coming up) due to physics and literal flippin’ bias. 🧪 arxiv.org/abs/2310.04153 [bsky, 7 points, 1 comments]
- Well this is just devastating news for randomized algorithms arxiv.org/abs/2310.04153 [bsky, 6 points, 2 comments]
- Fair coins tend to land on the same side they started: Evidence from 350,757 flips arxiv.org/abs/2310.04153 Contradicts this paper: www.tandfonline.com/doi/abs/10.1... [bsky, 4 points, 2 comments]
- And there is a new version with a correction citing all three authors, many thanks 🙏: arxiv.org/abs/2310.041... [bsky, 4 points, 0 comments]
- Empirical evidence supporting this prediction. [bsky, 3 points, 1 comments]
- Die fabelhafte Welt der Mathematik: Nach 350 757 Würfen steht fest: Münzwurf ist nicht fair [lemmy, 3 points, 3 comments]
- This appears to be the paper: arxiv.org/abs/2310.04153 #philsci [bsky, 2 points, 0 comments]
- Fair coins tend to land on the same side they started [hn, 2 points, 0 comments]
- When a person flips a coin, it has a 51% chance of landing on the same side it started: arxiv.org/abs/2310.04153 [bsky, 2 points, 0 comments]
- Абе и там има проблеми: arxiv.org/pdf/2310.04153. Хвърлянето на реалистична монета по-сложен физически (и психологически) процес, отколкото си даваме сметка. Като я мяткаш монетата, гледай да е някоя [bsky, 1 points, 0 comments]
- "In a preregistered study we collected 350,757 coin flips to test the counterintuitive prediction... that when people flip an ordinary coin, it tends to land on the same side it started... Our data le [bsky, 1 points, 0 comments]
- Heads! arxiv.org/abs/2310.04153 [bsky, 1 points, 0 comments]
- A coin toss is not really 50/50. What does this mean for binomial distributions?? Are we going to have to rewrite probability theory...? arxiv.org/pdf/2310.041... [bsky, 1 points, 0 comments]
- I am sure that you knew the following amazing paper: arxiv.org/abs/2310.04153 [bsky, 1 points, 0 comments]
- Did you know that when you flip a coin, it's got a 51% chance of landing on the same side it started? 😮 Check out this wild paper that collected data from over 350,000 coin flips: arxiv.org/abs/2310. [bsky, 1 points, 0 comments]
- Thing I learned today: A group of people recently made a gigantic coin-throwing experiment and showed that fair coins typically land on the same side they originally showed 50.8% of the time. arxiv.or [bsky, 1 points, 0 comments]
- Gotta take this into account now arxiv.org/abs/2310.04153 [bsky, 1 points, 0 comments]
- 今年のイグノーベル賞、コイントスで実験した結果で前のコインの向きと同じになる確率が高くなるという研究でしたね。ならサイコロでもそうなっておかしくないのかな。 arxiv.org/abs/2310.04153 [bsky, 1 points, 0 comments]
- イグノーベル確率賞は「コイン投げをしたとき最初上にある面と同じ面が出やすいことを理論と35万757回の実験によって示したことに対して」 #イグノーベル賞 arxiv.org/abs/2310.04153 [bsky, 1 points, 0 comments]
- Fair coins tend to land on the same side they started: Evidence from 350,757 flips [bsky, 0 points, 0 comments]
- Humans tossing a fair coin have 51% chance to get the same side! 😱 arxiv.org/abs/2310.04153# [bsky, 0 points, 0 comments]
- How to get a marginal gain in a coin toss: bet on it landing on the side that was uppermost when it started. arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
- 昨年10月に公にされたこのプレプリントでは、いわゆるコイン投げは完全にランダムな過程ではないことを35万回以上の試行によって、結論付けた。曰く、コインをトスするときに表にあった面が再び表に着地する確率が1％ほど大きいという。その原因はコインが飛ぶ間の回転軸のズレにあるという理論を援用しているが、ちょっと疑問。現実にはトスを上げる際の力がそれほどランダムではないから、いつも同じ結果になりがちなのでは [bsky, 0 points, 0 comments]
- cashless society when? arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
- And if you get enough of them you can do some really fun statistics! arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
- Soweit liebe ich es, aber ich liebe es noch mehr, wenn ich Tabelle 1 angucke und anfange zu rechnen. Bartoš et al. (2023). Fair coins tend to land on the same side they started: Evidence from 350,757 [bsky, 0 points, 1 comments]
- Jetzt wisst ihr auch, auf welche Seite der Münze ihr wetten sollt :) Spannendste Studie diese Woche [bsky, 0 points, 0 comments]
- Something I just learned about, which could come in handy if I’m observant enough. arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
- Damn, yo. Can't even have a fair coin flip anymore! arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
- Forget everything you ever learned about flipping coins! arxiv.org/abs/2310.04153 [bsky, 0 points, 0 comments]
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