está claro que cada tirada es 50% haya salido mil veces caras antes o no.
Esa es la teoria pura y dura para una tirada individual, pero cuando son rachas de tiradas viene bien mirar el pasaje del libro de Nassin Taleb y como crítica esta forma de pensar clásica dela estadística. Yo no apostaría cara a una moneda que ha salido 9 veces cara (suponiendo que la moneda no está trucada.
NNT (that is, me): Assume that a coin is fair, i.e., has an equal probability of coming up heads or tails when flipped. I flip it nineny-nine times and get heads each time. What are the odds of my getting tails on my next throw?
Dr. John: Trivial question. One half, of course, since you are assuming 50 percent odds for each and independence between draws.
NNT: What do you say, Tony?
Fat Tony: I’d say no more than 1 percent, of course.
NNT: Why so? I gave you the initial assumption of a fair coin, meaning that it was 50 percent either way.
Fat Tony: You are either full of crap or a pure sucker to buy into that “50 pehcent” business. The coin gotta be loaded. It can’t be a fair game. (Translation : It is far more likely that your assumptions about the fairness are wrong than the coin delivering the ninety-nine heads in ninety-nine throws.)
El resto de la explicacion aqui: http://markamok.com/2010/04/a-conversation-with-fat-tony-and-dr-john/