1, number n individuals in the population.
2. Write the number on the number label, put the number label in the container and stir it evenly.
3. Take a batch from it at a time, and take it n times without putting it back. The lottery method is a method of numbering each unit 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.