Probability Theory and Mathematical Statistics . Methods of mathematical statistics and their implementation in the Mathcad environment" is a unique manual created by a team of authors, which will become an indispensable assistant for students, graduate students and anyone interested in statistics and probabilistic methods. In today's world, where data plays a key role in decision-making, understanding the fundamentals of probability theory and statistics is becoming a necessary skill. This book offers the reader a deep dive into the world of mathematical statistics, starting with the basics and ending with more complex concepts. The authors have carefully worked out the material to make it accessible and understandable to a wide audience. Readers will be able to learn about the different methods of data analysis, evaluating their application in practice. The book includes many examples and tasks, which allows not only to theoretically master the material, but also to apply it in real situations. One of the key features of this publication is its practical focus. The authors focus on the implementation of mathematical statistics methods in the Mathcad environment, which makes the study more interactive and exciting. Mathcad is a powerful tool for performing mathematical calculations, and using it in the learning process allows the reader not only to learn the theory, but also to learn how to apply it in practice. This is especially true for students of technical and economic specialties, as well as for professionals working with data. The book will be interesting not only for students and graduate students, but also for practitioners, researchers and anyone who wants to expand their knowledge in the field of statistics and data analysis. It is suitable for readers with different levels of training: both for beginners and for those who already have some experience in this field. The topics covered in the book cover a wide range of issues, from the basic concepts of probability theory to more complex methods such as regression analysis and hypothesis testing. The topics raised in the book are relevant and in demand in the modern world. Statistics and data analysis play an important role in various fields: from medicine and social sciences to business and engineering. Understanding these methods allows you to make more informed decisions, which in a rapidly changing world is an invaluable advantage. The book will help readers develop the critical thinking and analytical skills needed to work with data. The style of the authors is distinguished by clarity and logical presentation, which makes the material accessible for understanding. They use many real-life examples, allowing the reader to see the practical application of theoretical concepts. This makes reading not only useful, but also fascinating. In addition, the work of the team of authors allows combining different points of view and approaches, which enriches