The behavior of any real system is a process to a greater or lesser degree probabilistic. As a rule, it is impossible to specify exactly which external influences and internal mechanisms of interaction of the system components will be decisive in the future. As a consequence, we cannot accurately predict the behavior of the system. We can only talk about the probability that, in the future, the system will come to a particular state. While the problem of the probabilistic description of all possible future states of the system is very difficult to answer, it is often enough, for research purpo.