Refer to the Process Safety Progress (December 2004) and U.S. Chemical Safety and Hazard Investigation Board study of industrial accidents caused by management system failures, Exercise 2.150. The table below gives a breakdown of the root causes of a sample of 83 incidents. Are there significant differences in the percentage of incidents in the four cause categories? Test using a = .05.

Management System Cause ______________ Number of Incidents

Engineering & Design ..........................................27

Procedures & Practices .........................................24

Management & Oversight ......................................22

Training & Communication ...................................10

Total ..............................................................83