The expected result of a trial in a casino game needs to be independent of other trials . In other words , let ' s say you have a 0 . 0001 % chance to hit a jackpot in a slot machine . You hit the jackpot . On the next pull , your chance of hitting the jackpot needs to still be 0 . 0001 %. You can ' t have a program say we have a target payout of 97 %, we just made a massive payout so for the next 1000000 pulls we ' re going slightly skew the odds in our favor until we get back to 97 % actual payout . Small sidenote , The Wizard of Odds used to still does ? stories on the backend software behind online casinos , and one of the most popular providers includes this skewing as a feature going as far as complete and silently disabling jackpots .