Slot Machine Odds

PJM1206 · #1 05-10-2007, 07:23 AM

I was recently at Foxwoods and watching my wife and sister-in-law playing the slots. As I watched I began wondering what the odds were of hitting the jackpot. So.... I called over an attendant and he said about a million to one.. Hmmmmm not so fast I thought so I asked if he could show me the inside of the machine so I could see how many symbols/stops per reel. As it turns out there were 3 reels and 11 symbols per real. There were six different symbols ( a double dimanod, Seven, 1 bar, 2 bars, 3 bars, and a cherry). He closed the machine up before I could see how many of each were on the reel so I noted the patterns as my wife played. I have included below the # of each symbol on each reel. Two part question: based on the above if there is only one double diamond on each wheel (3 double diamonds is the jackpot) then is it correct to calcualte the odds as (11)(11)(11)= 1,331 or 1330 to 1?... Part 2 if one reel has 2 double diamonds symbols and the others have one is it correct to assume (11)(5.5)(11)= 665.5 or 664.5 to?

These odds do not seem as bad as I was percived nor what I was told by the attendant (a million to one.

Thanks for the help

PJM1206 · #2 05-10-2007, 07:29 AM

Here was the info on the reels:

Reel 1 Reel 2 Reel 3
1 DD 1 DD 2 DD
1 3-bars 2 3-bars 3 3-bars
1 2-bars 2 2-bars 2 2-bars
3 1-bar 2 1 bar 3 1-bar
2 7s 2 7s 1 7
3 cherries 2 cherries 0 cherries

Tom1975 · #3 05-10-2007, 09:24 AM

Slot machines don't work that way any more. The reels are just for show, they play no part in determining whether or not you win. When you "spin", a random number generator inside the machine picks a number. Most numbers correspond to a loss, some correspond to a win. It then moves the reels around to the proper position to reflect what it has chosen.

cardcounter0 · #4 05-10-2007, 11:21 AM

The reels do not mean anything. The win or loss is determined by the internal RNG. The slot then spins the reels and stops them automatically in the position determined by the RNG.

So the reels could have 20 watermellons on it, and 1 cherry. If the RNG is programmed to come up cherry, then the reel will always spin and stop at the lone cherry symbol. Physically, the reel should stop on watermellon 20/21 times, but the RNG has control so the reel will stop on cherry 21/21 times.

PJM1206 · #5 05-10-2007, 07:40 PM

Thanks..... How would can you go about finding the odds on these machines? Is it possible?

cardcounter0 · #6 05-11-2007, 01:29 PM

[ QUOTE ]
Thanks..... How would can you go about finding the odds on these machines? Is it possible?

[/ QUOTE ]

Well, obviously the maker of the machine knows, and the casino knows. They order the machines with a specific payback RNG. 98% payback, 96% payback, etc.

The exact distribution of these payouts is up to the maker. They have probably done a huge amount of testing to see how many small payouts are needed with what exact frequency to keep the pigeons pushing the buttons.

But software-wise, I know the RNG usually looks at the reels as having 256 unique positions. So I would assume the highest jackpot is 256 x 256 x 256 or 1:16,777,216.
They might adjust and add a few more big winner combinations to bring it down if the big payoff isn't that large.

Another interesting point is they can manipulate the non-winning combinations. Maybe make a "teaser" loser BAR - BAR - ZIP combination with the winning BAR right above or below the payline occur more often than chance. Just another trick to keep the addicts playing.

I know in Missouri the gaming commission requires the casino to disclose the odds. So if you ask, with some persistance, eventually they will dig up a little chart showing the odds of each payoff.

In Indiana, I was in the casino once when they were changing the payoffs, and the gaming commission was present and would not allow the machines to be put into service until they documented the proper RNG chips were in the machines. Vegas has much the same procedures.