OIT Quality Assurance and Improvement 2 — Questions and Answers
Question 1: Which statistical tool is used to identify the most significant causes of defects by ranking them from most to least frequent?
- Control chart
- Pareto chart (Correct answer)
- Scatter diagram
- Histogram
Correct answer: Pareto chart
A Pareto chart ranks defect causes by frequency to help teams focus on the vital few issues causing the most problems.
Question 2: In a quality management context, what does 'process capability' (Cp) measure?
- The speed at which a process runs
- The ability of a process to produce output within specification limits (Correct answer)
- The number of defects per million opportunities
- The total cost of quality failures
Correct answer: The ability of a process to produce output within specification limits
Process capability (Cp) measures how well a process can produce parts or outputs that fall within defined specification limits.
Question 3: What is the primary purpose of a fishbone (Ishikawa) diagram in quality improvement?
- Tracking defect trends over time
- Identifying and organizing potential root causes of a problem (Correct answer)
- Displaying the distribution of measurement data
- Monitoring process control limits
Correct answer: Identifying and organizing potential root causes of a problem
A fishbone diagram visually maps potential root causes of a problem into categories such as Man, Machine, Material, Method, and Environment.
Question 4: A worker notices that a dimension is consistently near the upper control limit on a control chart but never exceeds it. This is BEST described as:
- Normal process variation
- A process that is out of control
- A non-random trend requiring investigation (Correct answer)
- Acceptable because limits are not exceeded
Correct answer: A non-random trend requiring investigation
Consistently clustering near a control limit indicates a non-random pattern (trend or bias), which warrants investigation even if limits are not breached.
Question 5: Which of the following BEST describes 'first pass yield' (FPY)?
- The total units produced in a single shift
- The percentage of units that complete a process without any rework or rejection (Correct answer)
- The ratio of scrap cost to total production cost
- The number of inspections performed per shift
Correct answer: The percentage of units that complete a process without any rework or rejection
First pass yield measures the percentage of units that pass through a manufacturing process correctly the first time, without rework.
Question 6: What is the main objective of a Measurement System Analysis (MSA) or Gauge R&R study?
- To calibrate instruments to ISO standards
- To evaluate the variation contributed by the measurement system itself (Correct answer)
- To determine the correct specification limits
- To identify which operators produce the most defects
Correct answer: To evaluate the variation contributed by the measurement system itself
A Gauge R&R study quantifies how much of the total observed variation is due to the measurement system (gauge and operators) versus actual part variation.
Question 7: In the context of quality, 'voice of the customer' (VOC) is used to:
- Record customer complaints in a log
- Translate customer needs and expectations into measurable product requirements (Correct answer)
- Train customer service representatives
- Audit supplier quality performance
Correct answer: Translate customer needs and expectations into measurable product requirements
VOC is a process for capturing customer requirements and translating them into specific technical and quality specifications for a product or process.
OIT Quality Assurance and Improvement 2
Which statistical tool is used to identify the most significant causes of defects by ranking them from most to least frequent?