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Persi Diaconis, 2004: http://statweb.stanford.edu/~susan/papers/headswithJ.pdf http://statweb.stanford.edu/~susan/papers/headswithJ.pdf and http://news.stanford
by GFK_of_xmaspast 11y ago
Persi Diaconis, 2004: http://statweb.stanford.edu/~susan/papers/headswithJ.pdf http://statweb.stanford.edu/~susan/papers/headswithJ.pdf and http://news.stanford.edu/pr/2004/diaconis-69.html http://news.stanford.edu/pr/2004/diaconis-69.html
- kybernetikos 11y agoThanks for those links, really interesting. Summary for anyone who hasn't read them: Diaconis did detailed analysis and ran experiments and found that coins are biased to land the way they start, but it's a small bias in normal use (51%). The article also claims that he has trained himself to reliably flip coins so they land the same every time. Interesting that it seems to contradict the article linked here.
- ziyao_w 11y agoAnd some more magic by Persi: https://youtu.be/ZdA7TeoZD_g?t=2m10s https://youtu.be/ZdA7TeoZD_g?t=2m10s
- davidb_ 11y agoThat's a neat trick. Based on the article and rewatching the video, he's not actually flipping the coin. > In Section Three we prove that the angle ψ between M and the normal to the coin stays constant. If this angle is less than 45 ◦ , the coin never turns over. It wobbles around and always comes up the way it started. Magicians and gamblers can carry out such controlled flips which appear visually indistinguishable from normal flips.
- steve19 11y agoHe refers to it at the end of that video clip as tossing. looking closely that's pretty much what he is doing. it looks like he might be flipping it once during the toss for effect. Such a slow rotation allows him to easily catch it at the right moment.