It is independent and identically distributed. Based on probability theory, it studies the statistical regularity of a large number of random phenomena. The task of descriptive statistics is to collect data, organize grouping, compile frequency distribution table, draw frequency distribution curve and calculate various characteristic indexes.

Describe the concentration trend, deviation trend and skewness of data distribution frequency distribution. Inference statistics is based on descriptive statistics, and infers and predicts the population according to the regularity summarized by sample data.

An action plan based on statistical inference or prediction and considering the consequences of actions (expressed in the form of economic losses). The purpose is to make the loss as small as possible, or conversely, to make the gain as large as possible.

For example, if a store wants to decide the purchase quantity of a product this year, the statistician of the store predicts that the sales volume of the product this year will be 1000 pieces. Assuming that each overstocked product loses 20 yuan, and one product sold less loses 65,438+00 yuan, then the decision on purchasing quantity should be made accordingly.

Baidu Encyclopedia-Mathematical Statistics