MATHEMATICAL EXPECTATION AND DISPERSION IN BETS
Above, we have already defined the terms expectation and variance…
Now it's time to look at them in practice.
For ease of understanding, again, let's take our coin example. We have already written that the probability of getting heads and tails is 50% each, but in practice one of the sides can come up many times in a row.
So, many bettors believe that every losing bet on an event with a 50% probability of passing only increases the likelihood of winning the next time (22 bet app to read more). That is why the Martingale strategy is so popular among many, it is also catch-up. It assumes the following: with each subsequent bet, the player doubles the amount of the previous one in order to win back and make a profit. But here you need to understand that in most cases such a strategy leads to a loss in the distance just because of the variance.
If you rely only on the mathematical expectation, then after a loss there should come a win, but this does not happen, and the deviation from the mathematical expectation is especially noticeable at a short distance. For example, if a player makes 10 bets, he can easily lose 7 of them. After 50 bets, he can already have 22 wins and 28 losses, and after 100 - 46 wins and 54 losses. Of course, it can also be the other way around, here it is already a matter of chance.
As you can see, the result evens out over the course, but 100 bets is too short a distance for evaluating the results like here 22 bet apk . You need to look at 1000 and the balance turns out to be even at best, and often negative because of the margin. So how do you beat the bookmaker? - Now we will tell you.
Read more in Wikipedia: Probability Theory