The number of people killed by 30 to 60 trial who received the management body in conjunction with the knowledge of the group control number: 30 people get knowledge only:
The experimental group consisted of 60 people, 30 of whom have been with the program management body of knowledge about ergonomics. And a control group of 30 people to gain knowledge of ergonomics alone.
The 60 people by the group of 30 people. The administrative body with the ergonomics and the control group of 30 people. To gain knowledge of ergonomics alone.