Coin Slot Magazine - #056 - 1979 - October [International Arcade Museum]
WHAT ARE THE PAYOUT ODDS
FOR YOUR THREE-REELER?
By David L Saul
ally, slots obey the laws of probability.
You don't have to be a mathematician to find
out.
In ma
chine terms, we assume the following:
If you can count symbols on reels and juggle
numbers well enough to keep a checking account
1. that each reel, after being started, is equally
balanced most of the time, you can quickly ac
quire the skills needed to figure payout percent
likely to come to rest at any one of its pos
ages for your favorite one-arm bandit. This article
sible stop positions, and
2. that each reel operates independently of the
tells you how to find your chances of hitting any
others.
of the various payout combinations, the odds of
These conditions, of course, may not hold in
winning or losing on a given play, and much more,
it'll tell how to find out what percent of total
every case.
money played can be expected to wind up in the
is a whiz at skill stop manipulation may be able
A skilled rythym player or one who
cash box, and with a little practice, you can even
to "bend" these a bit.
perform such feats as figuring the odds against
break them down completely and "clean out" cer
He might even be able to
hitting three oranges twice in a row, or of walking
tain machines.
up to a machine (FUTURITY owners take note)
render normal payout odds meaningless.
and feeding x number of coins in without hitting
purpose at hand, we shall assume that such player
a paying combination.
skills are either a "lost art", won't be exercised
The list goes on and on.
In such a case, player skill would
For the
on your machines, or never existed in the first
place. You can take your choice!
To accomplish all this we'll need to introduce
some basic principles of probability and show how
they apply to slots.
Since we've already been tossing the term "prob
Although probability theory
ability around quite a bit, we'd better define exact
can get to be a pretty hair raising branch of mathe
ly what we are talking about. Probability is gener
matics, it turns out that one-arm bandit payouts
ally expressed as a number whose value can range
are among the easiest probability problems that
one is likely to encounter.
from zero to one. A plain old fraction. This num
Maybe the machines
ber represents the relative frequency of occurrence
were designed to be that way. Who knows?
of a chance event when a large number of "trials"
take place.
Before launching into any examples, we need
A trial can be a coin flip, a pull of a
handle, or whatever is needed to produce a chance
to take note of the fact that a slot machine func
event.
tions, or at least is designed to function, purely
than some occurrence of interest whose outcome
as a game of chance.
or result isn't known until after a trial takes place.
Under practical conditions,
The chance event itself is nothing more
the speeds and running times of reels are subject
to variations that (presumably, at least) can't be
controlled
or
predicted
by a player.
An event that can't happen at all has a prob
Also the
ability of zero.
starting points for each spin aren't obvious if there
are multiple symbols of the same kind spread a-
round each reel
in various stop positions.
The
lemon symbols is zero.
om
m. of c one,
:
rom -museu
f
d
e
ade is truly
chine's operation.
Whether
process
oad . this
l
c
r
n
a
ow that would
random in a D
way
ww satisfy a nit-picking
://w to doubt. But the fact
college professor tt is p subject
h
mechanical
process of selecting symbols strictly
For example, the probability of
hitting a lemon on a middle reel that carries no
on a chance basis is fundamental to a slot ma
At the other extreme, an
event that is certain to occur has a probability
or unity.
For example, the probability
of a spinning reel stopping on one of its symbols
(we don't care which one) is unity if its stop mech
anism is working properly.
Most probabilities of
interest lie somewhere between these extremes.
that slots (where used for gambling) successfully
For example, a flipped coin has a probability of
and consistently extract money from the playing
.5 of coming up heads.
public is subject to no doubt whatever!
machine
© The International Arcade Museum
Function
10
reel
that
Likewise, a ten-stop slot
carries
five
cherry
symbols
http://www.arcade-museum.com/