Hello! What is the variance? What is my risk of loss? What is the variance of a gaming machine

To calculate this figure you need to know higher mathematics! Well, maybe there are mathematics among us ?!
The program works so as to interest and engage the player, but not to allow him to receive a mega bonus.
If there was no opportunity to win the main prize, there would be no players.
Every player wants to win and dreams of the main prize of course. The platform needs to convince players that winning the main prize is quite possible.
It is important for people that the casino or gambling platform play with them honestly. Let the probability of winning is not very high, but the winnings should fall from time to time, then the players will play more.