5 ms·

i don't think you need to go to such visible lengths to bias a coin. if one face of the coin was weighted more (by using a heavier alloy), it would likely bias

i don't think you need to go to such visible lengths to bias a coin. if one face of the coin was weighted more (by using a heavier alloy), it would likely bias it simply because when/if it bounces, it would be more likely to land with that face down. maybe?

carbocation 15y ago
Yes, you could bias the coin in many ways. But the author chose an inexpensive method available to readers without experience in metallurgy.
- jackpirate 15y ago
  Also, based on how big of a bending angle you actually need to bias the coin, I doubt anything you could do would bias the coin without being very noticeable.
Codayus 15y ago
It's actually hard - and perhaps impossible - to bias a coin by weighting one face. It's not a very well studied area, but according to what info I can find[1], as general rule, you should assume that if some shady stranger in a bar is offering to bet money on the outcome of a coin flip, the coin is going to be perfectly fair. (Also, you can always work around a possibly biased coin by instead flipping the coin twice, and repeating the process until you get HT or TH, and then using the first element of the pair as the result.) On the other hand, it is well established that the process of flipping a coin is biased, and a skilled coin flipper can produce whichever result he wants with a probability approaching unity. And there's NO way to work around that bias. The lesson here is probably "don't wager money on the outcome of coin flips". [1]: http://www.stat.berkeley.edu/~nolan/Papers/dice.pdf http://www.stat.berkeley.edu/~nolan/Papers/dice.pdf
carbocation 15y ago
Codayus, if you notice this, you appear to be hellbanned (all of your comments for the past 10 days are dead, including the one in this thread). I looked over your comment history and I can't understand why this would be, so I'm alerting you in case you want to ask PG for a reprieve.
- bobds 15y ago
  Easy way to check if you are hellbanned: Visit the .org website and you won't be logged in. http://news.ycombinator.org/submitted?id=YOUR_USERNAME_HERE http://news.ycombinator.org/submitted?id=YOUR_USERNAME_HERE If all your latest comments are grey, shed a tear for the time you've wasted.
- tptacek 15y ago
  I'm not a "having conversations with 'pg over email" kind of guy, but I've found him pretty responsive on "it doesn't look like this person should be banned" mails. Next time, you might find it less effortful to bang out a quick mail to pg@ycombinator.com to fix stuff like this. (I don't know what the deal is with accidental hellbanning, but it seems to happen with some regularity). I mailed him already for this user, though.
  - carbocation 15y ago
    Thank you. I'll try that approach next time.
wvoq 15y ago
This fun article by Andrew Gelman and Deborah Nolan shows that it's practically impossible to create a coin that will demonstrate a bias when flipped, unless the coin is allowed to bounce: http://www.stat.columbia.edu/~gelman/research/published/diceRev2.pdf http://www.stat.columbia.edu/~gelman/research/published/dice...

carbocation 15y ago

Yes, you could bias the coin in many ways. But the author chose an inexpensive method available to readers without experience in metallurgy.

jackpirate 15y ago
Also, based on how big of a bending angle you actually need to bias the coin, I doubt anything you could do would bias the coin without being very noticeable.

Codayus 15y ago

It's actually hard - and perhaps impossible - to bias a coin by weighting one face. It's not a very well studied area, but according to what info I can find[1], as general rule, you should assume that if some shady stranger in a bar is offering to bet money on the outcome of a coin flip, the coin is going to be perfectly fair. (Also, you can always work around a possibly biased coin by instead flipping the coin twice, and repeating the process until you get HT or TH, and then using the first element of the pair as the result.) On the other hand, it is well established that the process of flipping a coin is biased, and a skilled coin flipper can produce whichever result he wants with a probability approaching unity. And there's NO way to work around that bias. The lesson here is probably "don't wager money on the outcome of coin flips". [1]: http://www.stat.berkeley.edu/~nolan/Papers/dice.pdf http://www.stat.berkeley.edu/~nolan/Papers/dice.pdf

carbocation 15y ago

Codayus, if you notice this, you appear to be hellbanned (all of your comments for the past 10 days are dead, including the one in this thread). I looked over your comment history and I can't understand why this would be, so I'm alerting you in case you want to ask PG for a reprieve.

bobds 15y ago
Easy way to check if you are hellbanned: Visit the .org website and you won't be logged in. http://news.ycombinator.org/submitted?id=YOUR_USERNAME_HERE http://news.ycombinator.org/submitted?id=YOUR_USERNAME_HERE If all your latest comments are grey, shed a tear for the time you've wasted.
tptacek 15y ago
I'm not a "having conversations with 'pg over email" kind of guy, but I've found him pretty responsive on "it doesn't look like this person should be banned" mails. Next time, you might find it less effortful to bang out a quick mail to pg@ycombinator.com to fix stuff like this. (I don't know what the deal is with accidental hellbanning, but it seems to happen with some regularity). I mailed him already for this user, though.
- carbocation 15y ago
  Thank you. I'll try that approach next time.

wvoq 15y ago

This fun article by Andrew Gelman and Deborah Nolan shows that it's practically impossible to create a coin that will demonstrate a bias when flipped, unless the coin is allowed to bounce: http://www.stat.columbia.edu/~gelman/research/published/diceRev2.pdf http://www.stat.columbia.edu/~gelman/research/published/dice...