Slots USA / THE EDITION
The glossary
A shared vocabulary for the numbers and systems behind the reels.
- Expected value
A probability-weighted average of possible outcomes. It is a property of the model, not a guarantee for one observation.
Read the explanation- Hit frequency
The proportion of events that meet a stated definition of a hit. The definition and denominator must accompany the number.
Read the explanation- Independence
A relationship in which knowing one event does not change the probability of another.
Read the explanation- Observed return
A ratio calculated from recorded amounts returned and amounts input over a defined set of events.
Read the explanation- Paytable
A document associating defined outcomes with amounts under specified conditions. It may not disclose their probabilities.
Read the explanation- RNG
Random number generator. Its outputs are inputs to other system rules; the acronym alone does not describe the outcome distribution.
Read the explanation- RTP
Return to player. A theoretical value describes the model’s expected return relative to input; an observed value describes recorded results.
Read the explanation- Standard deviation
A measure of spread equal to the square root of variance, expressed in the same units as the observations.
Read the explanation- Volatility
Variation in outcomes. Descriptive ratings need their method before they can be compared quantitatively.
Read the explanation