Re: [math-fun] how to test whether a coin is fair

Gene has it exactly right: a) you need to decide what you mean by 'fair' ... Expectation of a Head = 0.5 +- epsilon ... but what's epsilon? b) Bayesian inference totally takes care of this just decide what your prior belief in the coin is .... e.g., it's Probability of throwing a Head is 'x' ... for all x ... i.e. you know nothing to start with Of course, if it's not fair, you'll be tossing it a long time and getting increasingly incredulous. [ Greece will tell you that if it's a Euro, you don't need to toss it - it's not fair :-) ] Guy