Myth:
An event is either more or less likely if it has not happened for a long time.
Fact: Many people falsely believe, for example, that if one color has won several times in a row in roulette then the other color is overdue and will bet on it. While the ratio of reds to blacks will always approach 50/50 in the long term it can not be concluded that this will happen in the short term. It does not matter what the history of past spins is, every trial in games of luck like roulette are independent, and each color is equally likely to come up every time.
Myth:
People can generally win their money back if they have a losing streak.
Fact: This is simply not true and casinos exist because people don't win their money back. Think about it: how long would a casino that paid out more money than it took in be able to stay in business? The fact is that gamblers lose far more money than they win in these places.
Myth:
People can predict a coin is going to come up heads or tails when flipped.
Fact: Each flip of the coin is an independent event. It doesn't matter what came up in the previous flip. The chances of heads or tails coming up in a single flip are 50 per cent, regardless of how many times you flip the coin.
taken from
http://www.aplaceofhope.com/reports_gambling.html