PMI Scheduling Professional Certification (PMI-SP) Practice Exam

The term that represents the boundaries of common variation in a statistically stable process is known as control limits. Control limits are specific statistical thresholds that indicate the range within which the process variation is expected to occur when it is in a state of statistical control. They are derived from the process data and help in monitoring the stability of the process over time.

Control limits play a crucial role in quality control and process management, as they help identify when a process is deviating from its expected performance. When a measurement falls outside these limits, it signals that the process may be affected by special causes of variation that need to be investigated.

In contrast, other options like grade limits refer more to the classification of quality levels in products, quality thresholds involve the levels of quality that need to be met but do not indicate variability over time, and performance parameters can describe various metrics or indicators for success but do not specifically define the range of expected variation in a process.