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You can load a die but you can't bias a coin (2002) [pdf]

stat.columbia.edu

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Re: You can load a die but you can't bias a coin (2002) [pdf]

#3

Got a lot of respect for Andrew Gelman, but it's too bad he didn't cite Persi Diaconis: http://statweb.stanford.edu/~susan/papers/headswithJ.pdf

The Gelman-Nolan paper is from 2002; the Diaconis et al. paper is from 2007, and cites Gelman-Nolan. Gelman and Nolan are pretty smart, but they don't have a time machine.

Re: You can load a die but you can't bias a coin (2002) [pdf]

#5
It's already biased towards the face that is facing up to start. With practice or by accident, you can toss it so that it wobbles but doesn't actually flip over. A casual observer cannot tell the difference.

Explained in http://www.amazon.com/Heads-Or-Tails-Gary-Kosnitzky/dp/B00FM...

Re: You can load a die but you can't bias a coin (2002) [pdf]

#6
post #5

It's already biased towards the face that is facing up to start. With practice or by accident, you can toss it so that it wobbles but doesn't actually flip over. A casual observer cannot tell the difference. Explained in http://www.amazon.com/Heads-Or-Tails-Gary-Kosnitzky/dp/B00FM...

TODO: Build a robot with precise enough control that it can flip a coin (properly flipping, not just wobbling) and then catch it in a desired state (either heads or tails) with substantial accuracy.

Re: You can load a die but you can't bias a coin (2002) [pdf]

#7

Got a lot of respect for Andrew Gelman, but it's too bad he didn't cite Persi Diaconis: http://statweb.stanford.edu/~susan/papers/headswithJ.pdf

The Gelman-Nolan paper is from 2002; the Diaconis et al. paper is from 2007, and cites Gelman-Nolan. Gelman and Nolan are pretty smart, but they don't have a time machine.

Indeed Diaconis et al. cites Gelman-Nolan.

Re: You can load a die but you can't bias a coin (2002) [pdf]

#9
post #5

It's already biased towards the face that is facing up to start. With practice or by accident, you can toss it so that it wobbles but doesn't actually flip over. A casual observer cannot tell the difference. Explained in http://www.amazon.com/Heads-Or-Tails-Gary-Kosnitzky/dp/B00FM...

TODO: Build a robot with precise enough control that it can flip a coin (properly flipping, not just wobbling) and then catch it in a desired state (either heads or tails) with substantial accuracy.

That's a pretty cool idea! Let me know how it goes :) I think it's totally possible.

For your viewing pleasure:

https://www.youtube.com/watch?v=tIIJME8-au8

Cheers.

Re: You can load a die but you can't bias a coin (2002) [pdf]

#10
If you go beyond the title and read the paper carefully, what it states is if you spin a coin rapidly in the air with a horizontal spinning axis and catch it in the air, then weighting the coin doesn't bias it. If you throw a coin in other ways (e.g. let it land on a surface), then you can of course bias a coin.
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