Random number method: it is a method of sampling by using random number table. Random number table is also called random number table. According to the requirements of coding digits, 10 natural numbers are automatically shaken out from 0 to 9 by a special code shaker or computer, or a certain number of numbers generated by computer are compiled into a table for future reference. Any number in this list is equally likely to appear. When using this table to extract samples, the tedious sampling procedure can be greatly simplified. The disadvantage is that it is not suitable for a large number of individuals in a group.
Draw lots: It is a method of numbering the units of the survey population first, and then randomly drawing numbers until enough samples are drawn. It is suitable for transactions with relatively large overall capacity. Because it is simple and easy to realize, it is widely used. The lottery method is also called the lottery method. It first numbers each unit of the survey population, and then randomly selects the numbers until enough samples are taken.