4 ms·
It's quite simple to implement a fair coin from a coin of unknown fairness. So simple, I put it in a children's book. http://carlos.bueno.org/2011/10/fair-coin
by aristus 13y ago
It's quite simple to implement a fair coin from a coin of unknown fairness. So simple, I put it in a children's book.
http://carlos.bueno.org/2011/10/fair-coin.html http://carlos.bueno.org/2011/10/fair-coin.html
- martijn_himself 13y agoVery nicely presented. How would you define 'simple'? While I can see the heuristic process is simple (i.e. flip twice and choose the first result in case of HT or TH) to follow, and you could arrive at the conclusion that this gets rid of bias through experiment, I don't find this intuitively simple at all. EDIT: I've also noticed that if I choose 'Suppose Heads comes up 50% of the time.' it says 'You'll need an average of 3.00 flips to get a fair coin.' If heads comes up 50% of the time then I have a fair coin, so shouldn't that be 1.00 flip?
- aristus 13y agoRe-deriving from scratch it is hard. No question about that. Magnetism doesn't make a ton of sense either, but it's simple to demonstrate. Intuitive and simple are not always the same thing. If your coin happens to be absolutely fair, it will require on average 3 flips to generate a fair flip via this method. The point is you don't know a priori whether a given coin is fair.
- martijn_himself 13y agoGreat reply, thanks, that makes a lot of sense. Very impressive work too on the book.