What is the purpose of a Control Chart?

The purpose of a Control Chart is to monitor process stability and variability. Control charts are statistical tools used in quality control to track performance and identify any variations in a process over time. By plotting data points in a time-ordered sequence, control charts help visualize whether a process is in control, meaning it operates consistently and predictably within established control limits.

The key feature of a control chart is its ability to distinguish between common cause variation, which is inherent to a process, and special cause variation, which indicates an anomaly or shift in the process that may need investigation or corrective action. This monitoring is crucial for maintaining consistent quality in products or services and for ensuring that any deviations from expected performance are quickly addressed.

In contrast, displaying data in a graphical format is a broader function that may not necessarily serve the specific goal of monitoring process quality. Determining the costs associated with a process relates to financial aspects rather than quality control, while collecting customer feedback for improvements focuses on external input rather than internal process monitoring. Thus, the specific objective of assessing process stability and variability through control charts is what distinguishes it as the correct answer.