In mathematics, variance is a measure of the dispersion of the probability density around its center of gravity. The term variance was coined in particular by the British statistician Sir Ronald Aylmer Fisher. In the world of gambling, variance refers to the payout structure of a slot machine. A basic distinction is made between low variance and high variance Slot machine games.
Many players particularly appreciate Slot machines with high variance. These are Casino games where wins are less frequent, but tend to be higher. This means that in several game rounds in a row, no win at all can be achieved here. But then it can suddenly come to large wins or Free spins series. High variance slots usually feature special bonus features such as Sticky Wilds, free spins or progressive Jackpot wins.
On the other hand, low variance slots are the games where payouts are more frequent but correspondingly lower. The idea is to keep players "happy" with fairly regular (smaller) wins. However, impressive high wins do not usually occur here. Overall, statistically speaking, the gaming balance remains relatively stable here over a longer period of time due to the many small wins. By the way, in many cases the term "volatility" is seen as synonymous with the term "variance" explained here.