ASQ Certified Quality Engineer (CQE) Flashcards

In statistical process control (SPC), what does 'common cause variation' refer to?

Answer: Inherent, natural variation in a process

Common cause variation is the natural, inherent variability in a stable process resulting from the system itself, not from specific identifiable causes.

Which control chart is used to monitor the proportion of defective items in a sample?

Answer: p chart

The p chart monitors the proportion (fraction) of defective items in samples of varying or equal size, making it an attribute chart.

What is the primary purpose of a Pareto chart in quality management?

Answer: To identify and prioritize the most significant causes of problems

A Pareto chart arranges categories by frequency or impact to identify the 'vital few' causes responsible for most problems, applying the 80/20 rule.

In a normal distribution, approximately what percentage of data falls within ±2 standard deviations of the mean?

Answer: 95.4%

Approximately 95.4% of data in a normal distribution falls within ±2 standard deviations of the mean, per the empirical (68-95-99.7) rule.

What does the process capability index Cpk measure?

Answer: How well a process meets specifications considering both spread and centering

Cpk measures process capability by considering both the process spread relative to specifications and how centered the process mean is within the specification limits.

Which sampling plan standard is most commonly referenced for attribute acceptance sampling in the U.S.?

Answer: ANSI/ASQ Z1.4

ANSI/ASQ Z1.4 is the standard acceptance sampling plan for attributes, defining procedures and AQL-based tables for lot-by-lot inspection.

What is the null hypothesis (H₀) in statistical hypothesis testing?

Answer: The hypothesis that assumes no difference or effect exists

The null hypothesis (H₀) assumes no difference, relationship, or effect exists between variables and serves as the default baseline assumption to be tested.