9. Is fat-free body weight or X-ray a better screen for selecting material handlers? 10. Briefly discuss the job severity index.

The choice between fat-free body weight and X-ray as a better screen for selecting material handlers depends on the specific requirements of the job. Fat-free body weight can provide an indication of a person's physical strength and endurance, which can be important for material handling jobs that require heavy lifting. On the other hand, an X-ray can reveal potential health issues that might affect a person's ability to perform the job safely and effectively, such as bone or joint problems. Therefore, both methods can be useful, but the choice between them should be based on a thorough job analysis.

The job severity index is a measure used to assess the physical demands of a job. It takes into account factors such as the amount of heavy lifting involved, the degree of bending or twisting required, the pace of work, and the amount of time spent standing or walking. The index is typically calculated by assigning scores to each of these factors and then adding them up to get a total score. The higher the score, the more physically demanding the job is considered to be. This index can be useful for job design, risk assessment, and the development of training and prevention programs.