CPIM Practice Exam

Which term refers to the limits on a control chart that indicate an out-of-control process?

1. Statistical limits

2. Control limits

3. Tolerance limits

4. Operational limits

The correct answer is: Control limits

Control limits are the specific thresholds on a control chart that help determine whether a process is operating as expected or if it is out of control. These limits are derived from the statistical properties of the process data, typically set at three standard deviations above and below the process mean. When a data point falls outside these control limits, it signals that the process may be influenced by special causes of variation, prompting further investigation. The other terms mentioned have distinct meanings in the context of quality management. Statistical limits generally refer to broader statistical thresholds that may not specifically pertain to control charts. Tolerance limits define the acceptable range within which products or processes should operate concerning specifications, but they do not necessarily indicate process control. Operational limits can represent constraints within which a system operates but are not focused solely on the statistical implications of process control. Thus, control limits are the precise term that identifies when a process may be out of control.