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7 April 2000

Dear John,

If slot payouts are at random, how can slots be set to pay out a certain percentage?

Sharon

Dear Sharon:

A slot machine chooses the outcome of each spin at random from a pre-defined pool of possible outcomes. If you added up all the money you could win on all of the outcomes and divided by the total number of outcomes, you would get the payback percentage of the machine.

Let's say a machine has 1000 outcomes so the math is easy, even though a modern slot machine has many more possible outcomes. Let's also say that the total of all the money we can win on the 1000 outcomes is \$950. Dividing 950 by 1000, we see that this is a 95 percent payback machine.

The program in the machine will choose one of the 1000 outcomes at random to be the result of each spin. Over time, the odds of getting any particular outcome will get closer and closer to 1 out of 1000. And the amount of money the machine has paid back will get closer and closer to 95 percent of the money wagered on it because that's how much the pool of possible outcomes pays back.

In summary, slot machines can be set to pay out a certain percentage even though the result of each spin is chosen at random because the pool of outcomes pays out that percentage and every outcome is equally likely to be chosen on every spin.

Best of luck in and out of the casinos!
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@home.com.

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John Robison

John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

#### Books by John Robison:

The Slot Expert's Guide to Playing Slots
John Robison
John Robison is an expert on slot machines and how to play them. John is a slot and video poker columnist and has written for many of gaming’s leading publications. He holds a master's degree in computer science from the prestigious Stevens Institute of Technology.

You may hear John give his slot and video poker tips live on The Good Times Show, hosted by Rudi Schiffer and Mike Schiffer, which is broadcast from Memphis on KXIQ 1180AM Friday afternoon from from 2PM to 5PM Central Time. John is on the show from 4:30 to 5. You can listen to archives of the show on the web anytime.

#### Books by John Robison:

The Slot Expert's Guide to Playing Slots