Six Sigma Green Belt Certification Practice Exam

In a quality management system, what does the term "Cpk" measure?

1. Process capability

2. Defect density

3. Quality yield

4. Cost performance

The correct answer is: Process capability

Cpk, or Process Capability Index, is a key metric used in quality management systems to evaluate how well a process can produce output within specified limits. It measures the capability of a process to produce items that meet specifications, taking into account both the process variability and how centered the process is within the specification limits. A higher Cpk value indicates that the process is capable and produces a higher proportion of conforming products, meaning that the process operates effectively within the defined specifications. This metric allows organizations to assess their processes and identify areas for improvement to enhance efficiency and quality. Other choices do not accurately reflect what Cpk measures. Defect density typically refers to the number of defects found in a product relative to its total size or complexity, while quality yield relates to the amount of good product produced versus the total output. Lastly, cost performance focuses on the financial aspects of operations, rather than the capacity of the process to meet quality requirements. Thus, measuring process capability with Cpk is essential for understanding and improving manufacturing and service processes.