Coin Flip = 50/50 Odds... No Longer

[Jeremy]

They might as well tell us Metric isn't really our future at this point...

Conventional wisdom about coin flips may have been turned on its head. A global team of researchers investigating the statistical and physical nuances of coin tosses worldwide concluded (via Phys.org) that a coin is 50.8% likely to land on the same side it started on, altering one of society’s most traditional assumptions about random decision-making that dates back at least to the Roman Empire.

The team appeared to validate a smaller-scale 2007 study by Stanford mathematician Persi Diaconis, which suggested a slight bias (about 51 percent) toward the side it started on. The authors of the new paper conducted 350,757 flips, using different coins from 46 global currencies to eliminate a heads-tail bias between coin designs. (They also used a variety of people to rule out individuals with biased flipping techniques corrupting the results.) Regardless of the coin type, the same-side outcome could be predicted at 0.508, which rounds up perfectly to Diaconis’ “about 51 percent” prediction from 16 years ago.

Coin flips don’t appear to have 50/50 odds after all

A large team of researchers concluded that, when caught in the air, coin flips are 50.8% likely to land on the same side that started facing upwards.

www.engadget.com

 

[3TrueFans]

It was never 50/50 because tails never fails.

 

[xboxfever]

I’ve always looked at the top of the coin when doing a coin flip and picked whatever what was on top and seems to succeed 90% of the time for me. Apparently I’ve just been luckier doing that if it’s 50.8%.

 

[CoachHines3]

50/50 chance this study is correct

 

[Bipolarcy]

It was never 50/50 because tails never fails.

I thought there was some theory out there that heads appeared more often. Something to do with the mass of the coin and coins that had more weight on the tail side, which in a flip with fewer coin rotations that would tend to negate any weight discrepancy, meant the weighted side always landed on the bottom, so heads would prevail.

 

[nfrine]

Gambling at college games. Somebody better call the DCI.

 

[NorthCyd]

So basically it looks like the bias comes from how people flip the coin, and nothing to do with the coin itself.

 

[JM4CY]

Whenever she's said 50/50, it a lot closer to about .0005/99.9995

 

[Jeremy]

I thought there was some theory out there that heads appeared more often. Something to do with the mass of the coin and coins that had more weight on the tail side, which in a flip with fewer coin rotations that would tend to negate any weight discrepancy, meant the weighted side always landed on the bottom, so heads would prevail.

I think it depends on the coin used. There are some that have larger images or text on the back. But I've always figured that was probably the case with most US coins commonly used for flipping.

 

[ClonesFTW]

In college we had a lively discussion regarding something like this in Stat 326 - buddy of mine came back to Larch and flipped a quarter 1,200 times and recorded the results on a pizza box. Tails won 610 to 590, took 3 hours.

 

[Jeremy]

In college we had a lively discussion regarding something like this in Stat 326 - buddy of mine came back to Larch and flipped a quarter 1,200 times and recorded the results on a pizza box. Tails won 610 to 590, took 3 hours.

Still a virgin?

 

[Clonefan32]

In college we had a lively discussion regarding something like this in Stat 326 - buddy of mine came back to Larch and flipped a quarter 1,200 times and recorded the results on a pizza box. Tails won 610 to 590, took 3 hours.

 

[1100011CS]

50/50 chance this study is correct

50/50 it's half correct.

 

[cyclonespiker33]

Interesting that these results are based on catching the coin. Are the results the same if you let it land on the ground?

 

[coolerifyoudid]

In college we had a lively discussion regarding something like this in Stat 326 - buddy of mine came back to Larch and flipped a quarter 1,200 times and recorded the results on a pizza box. Tails won 610 to 590, took 3 hours.

"The authors of the new paper conducted 350,757 flips"

You needed to order a few more pizzas for your data-recording. You clearly lack the necessary conviction for this.

 

[BWRhasnoAC]

This has been studied before. It's always been a slight advantage to one side. They talked about this when I was in school 20 years ago.

 

[JP4CY]

 

[TrailCy]

It was never 50/50 because tails never fails.

If tails is so good why do I beat it about half the time?

 

[BillBrasky4Cy]

Whenever she's said 50/50, it a lot closer to about .0005/99.9995

Also applies to "it's a good size".

 

[Sigmapolis]

Technically it can land on its side, too. It's not likely but can happen.