BSIE Ergonomics & Human Factors Engineering 2 — Questions and Answers
Question 1: What is the purpose of a time-and-motion study in industrial engineering?
- To evaluate worker satisfaction
- To determine standard times for tasks by observing and timing work elements (Correct answer)
- To schedule machine maintenance intervals
- To calculate overtime pay rates
Correct answer: To determine standard times for tasks by observing and timing work elements
Time-and-motion studies break jobs into elements, time them with a stopwatch, apply performance ratings, and add allowances to establish standard times.
Question 2: In human reliability analysis, what does a Human Error Probability (HEP) of 0.01 mean?
- 1% of tasks are completed correctly
- There is a 1% probability of human error on a given task (Correct answer)
- There are 1 error per 100 workers
- 1% of errors are detectable
Correct answer: There is a 1% probability of human error on a given task
An HEP of 0.01 means there is a 1-in-100 probability that an operator will make an error when performing a specific task under defined conditions.
Question 3: Which principle of motion economy suggests that both hands should begin and end their motions simultaneously?
- Principle of symmetry
- Principle of simultaneous hand motions (Correct answer)
- Principle of minimum fixations
- Principle of continuous curved motion
Correct answer: Principle of simultaneous hand motions
The principle of simultaneous hand motions reduces idle time and cognitive load by synchronizing the start and finish of both hands' movements.
Question 4: What is 'vigilance decrement' in human factors engineering?
- The tendency to increase alertness over time on a monitoring task
- The decline in detection performance during prolonged signal-detection tasks (Correct answer)
- The increase in error rate due to physical fatigue
- The reduction in workstation lighting over a shift
Correct answer: The decline in detection performance during prolonged signal-detection tasks
Vigilance decrement refers to the decrease in an operator's ability to detect rare signals as the duration of sustained attention monitoring increases.
Question 5: Which body posture is most associated with lower back disorder risk on the job?
- Standing with arms at sides
- Seated with upright spine and feet flat
- Sustained forward trunk flexion combined with twisting (Correct answer)
- Walking on level surfaces
Correct answer: Sustained forward trunk flexion combined with twisting
Combined trunk flexion and rotation increases spinal compressive and shear forces substantially, raising the risk of intervertebral disc injury.
Question 6: In display design for control rooms, what does the 'primary zone' of a visual display refer to?
- The area where emergency alarms are placed
- The central field of view typically within ±15° from line of sight (Correct answer)
- The zone reserved for digital readouts only
- The area accessible without moving the head
Correct answer: The central field of view typically within ±15° from line of sight
The primary zone (±15° from the line of sight) is where frequently consulted displays should be located to minimize eye and head movement.
BSIE Ergonomics & Human Factors Engineering 2
What is the purpose of a time-and-motion study in industrial engineering?