1. Move your mouse randomly to generate the keys. �ƶ��������Ա����������Կ��
2. In our example, we draw randomly 1000 red points on the client area. ������������������ڿͻ��������1000����㡣
3. In these trials, people are randomly assigned to a "treatment" group, which benefits from the project, and a "control" group, which does not. �ڴ�������У����DZ������ָ�ɸ�һ�������ơ�С�飨����Ŀ�������ߣ��Լ�һ�������ա�С�飨���������ߣ���