Statistics is a branch of applied mathematics, which mainly uses probability theory to establish mathematical models, collect data from observation systems, make quantitative analysis and summary, and then make inferences and predictions, providing basis and reference for relevant decisions. It is widely used in various disciplines, from physics, social sciences to humanities, and even in the information decision-making of industry and commerce and government.

Statistics are mainly divided into descriptive statistics and inferential statistics. Given a set of data, statistics can summarize and describe these data. This method is called descriptive statistics. In addition, the observer establishes a mathematical model to explain its randomness and uncertainty in the form of data, thus inferring the steps and matrices in the research. This usage is called inferential statistic. Both of these usages can be called applied statistics. In addition, there is a subject called mathematical statistics, which is devoted to discussing the theoretical basis behind this subject.