Анотация: The main purpose of the present book is to help students to acquire such skills that are necessary to construct mathematical models (i.e., probability spaces) of various (social, economical, biological, mechanical, physical, etc) processes and to calculate their numerical characteristics. In this sense the last chapters ( in particular, chapters 14-15) are of interest, where some applications of various mathematical models( Markov chains, Brownian motion, etc) are presented. The present book consists of twenty one chapters. More of chapters are equipped with exercises (i.e. tests), the solutions of which will help the student in deep comprehend and assimilation of experience of the presented elements of probability theory and mathematical statistics. (из Въведение)