The slot odds of a slot machine are determined by how the slot machine was programmed. Their is a
random number generator that generates a number for a symbol on each of the reels. These numbers
are called virtual numbers and each number is assigned to a specific symbol on the slots reel.
The lower valued symbols on a paytable are given more virtual numbers and they will show up
more often, while the higher valued symbols are given less numbers and will not show on the
reels nearly as often as the lower valued symbols. This is calculated by the slot programmer.
Most slot machines are set to payout roughly 90-97% and this payout percentage is made up
of a high number of lower valued symbols showing up and paying out small winnings. As long
as a slot machine pays less than 100%, then the casino will end up winning over time. The
casinos will profit from the slot machines slowly over a long playing session by the player,
but the player will have several wins over the course of their slot playing session.
The slot jackpot can be won at anytime, and their is nothing that determines when it will
payout. It is a completely random event. It can pay out at anytime, and more than once.
The random number generator has no history and randomly determines what will happen.
The one thing that is guaranteed is that the slot machine will pay out 90-97% of
the time, but it will generate a moderate number of low value payouts and very
few high value payouts.