Slot Machine Appendix 1

Introduction

Between October 28 and November 1, 2000, I conducted a study consisting of 3976 plays on a 25-cent Double Strike machine located at the Silver Legacy in Reno. This specific slot machine, labeled as Silver Legacy machine number 4533, is a flat top produced by IGT. Below is the pay table showcasing its features. Some symbols were denoted with the term \"double,\" which doubled the prize total, except for the three red double sevens.

While playing, I meticulously recorded the positions of the payline symbols on each reel. By observing the symbols both above and below the payline, I was able to reconstruct the exact sequence of symbols on each reel. Subsequently, I entered the results of each play into a spreadsheet for analysis. The table below demonstrates the frequency of occurrence for each symbol during this experiment.

The chart below illustrates the number of observations for each reel at various stopping points, providing a clearer visual representation of the sample range.

Assuming that the weightings were accurate, the table presented below outlines the payout for each coin based on two coins played, the likelihood of each winning combination, and how they contribute to the overall return.

The last row of the preceding table indicates a theoretical return rate of 96.73% for two coins played, while the return for a single coin played is 96.62%. Furthermore, players can expect to achieve a win approximately 9.76% of the time. The calculated standard deviation for maximum coin play is 8.54. It's important to note that these figures are estimates drawn from actual gameplay results and should not be considered as exact measurements. The primary objective of this study was to demonstrate the concept of weighted reels rather than provide pinpoint return rates or reel weightings.

Based on the actual distribution and an assumption of 128 virtual stops, we can derive an educated approximation of the real wheel weightings. Below is a calculated guess of what those actual reel weightings might be.

According to the estimated weightings, the hit frequency stands at 9.77%, with a return rate of 95.53% when 1 coin is played and 95.66% when 2 coins are played.

Written by: Michael Shackleford