This textbook provides a comprehensive introduction to mathematical statistics principles underlying statistical analyses in the fields of economics, business, and econometrics. The selection of topics is designed to provide students with a substantial conceptual foundation from which to achieve a thorough and mature understanding of statistical applications within the fields. The examples and problems are intended to show the wide applicability of statistics in the fields, with the large majority having specific business and economic contexts. After introducing the concepts of probability, random variables, and probability density functions, the author develops the key concepts of mathematical statistics, notably: expectation, sampling, asymptotics, and the main families of distributions. The latter half of the book is then devoted to the theories of estimation and hypothesis testing with associated examples and problems that indicate their wide applicability in economics and business.