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How do they set the long-term payback on video keno?

28 September 2009

Hi,

I have been struggling with this question for a number of years and nobody seems to be able to answer it.

My question is on video keno, and the supposed random number generator they claim to have in there. If it was truly random how can the machine be set for different odds, IE: 86%-92%. If it were totally random there would be no setting possible.

Please try to make sense of this for me.

Many players have difficulty reconciling randomness with predictability in casino games. It all depends on what is random.

On a video keno machine, the random part of the game is what numbers will be drawn next. The non-random parts are that each number is equally likely to be drawn and how much you are paid for winning combinations.

Because each number is equally likely to be drawn, we can calculate the probabilities of matching x numbers when y are chosen. When the payoff for matching x numbers out of y is less than the true odds of matching that many numbers, the house is extracting its house edge.

There are two ways to change the long-term payback on a machine. We either have to change the probability of hitting a winning combination or we have to change how much we pay for a winning combination. On video keno, we can't change the probabilities of drawing the numbers, so we can't change the probabilities of hitting winning combinations. The only thing we can change is the pay table.

And that's how we set the long-term payback on the machine -- by changing the pay table. If we raise the payoffs for some winning combinations, we can raise the long-term payback to 92%, as in your example. Lower some payoffs and we can lower the long-term payback to 86%.

Best of luck in and out of the casinos,
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@comcast.net. Because of the volume of mail I receive, I regret that I can't reply to every question.

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