Slot Machine
Introduction
When it comes to gambling, the easier a game is to understand the worse the odds usually are. This is certainly the case with slot machines. Playing them is as easy as pressing a button. However, between the high house edge and fast rate of play, there is no quicker way to lose your money in a casino.
How They Work
Whether you're playing a 3-reel single-line game or a 5-reel 25-line game, the outcome of every bet is ultimately determined by random numbers. The game will choose one random number for each reel, map that number onto a position on the reel, stop the reel in the appointed place, and score whatever the outcome is. In other words, the outcome is predestined the moment you press the button; the rest is just for show. There are no hot and cold cycles; your odds are the same for every spin on a given machine.
Slot machines are just about the only game in the casino where the odds are not quantifiable. In other words, the player doesn't know how the game was designed, so it is difficult to look at an actual game to use as an example. So, to help explain how they work, I created the Atkins Diet slot machine (link). It is a simple, five-reel game with a free spin bonus round, much like IGT's Cleopatra game.
For information on how it works and all the odds, please visit my Atkins Diet par sheet.
For a more complicated example, featuring sticky wilds in the bonus, please try my Vamos a Las Vegas slot machine.
For information on how it works and all the odds, please visit my Vamos a Las Vegas par sheet (PDF).
Odds
The following table shows the casino win for Clark County Nevada (where Las Vegas is) for all slots for calendar year 2012. They define "slot" as any electronic game, including video poker and video keno. I've found video keno to be about equally as tight as reeled slots, but video poker has a much higher return. So, the return for reeled slots should be higher than these figures.
Source: Nevada Gaming Control Board, Gaming Revenue Report for December 2012 (PDF, see page 6).
Most players play penny video slots. Based on past research, I find the house edge on those to usually be set from 6% to 15%. In general, the nicer the casino, the tighter the slots.
