Possibility belongs to the field of mathematics, which mainly involves statistics and probability. Statistics and probability are one of the branches of mathematics that study random events and possibilities. Statistics studies how to collect, analyze and interpret data, and infer and predict the possibility of future events through probability. Probability theory studies the possibility of random events, the distribution of random variables, and the construction and application of probability models. These fields are widely used in various scientific and practical fields, such as physics, biology, economics, engineering and so on.