Data grouping is to divide the original data into different groups according to certain standardization according to the needs of statistical research, and the grouped data is called grouped data. The main purpose of data grouping is to observe the distribution characteristics of data. After grouping the data, the frequency of each group of data is calculated to form a frequency distribution table. When there are many continuous variables or variable values, group spacing is usually used for grouping. It divides all the variable values into several intervals in turn, and takes the variable values in this interval as a group. In the group spacing grouping, the minimum value of a group is called the lower limit; The maximum value of a group is called the upper limit. When using group spacing to group, we need to follow the principle of neither weight nor leakage. Not heavy means that a piece of data can only be assigned to one group and cannot be repeated in other groups; No omission means that the groups can be exhausted, that is, every item of data in all groups can be divided into a certain group and cannot be omitted.