Which statistical tool is often used to analyze process capability?

Control charts are a critical statistical tool used to analyze process capability as they help in monitoring and controlling a process over time. They display data points in time order and allow practitioners to distinguish between common cause variation (natural to the process) and special cause variation (resulting from external factors). By using control limits calculated from the process data, control charts enable teams to assess whether a process is operating within acceptable limits, which is essential for evaluating process capability.

Control charts are particularly useful for determining whether a process is stable and predictable, which is a prerequisite for further analysis of the process's capability. When a process is deemed stable, further calculations can be made using indices such as Cp, Cpk, Pp, and Ppk to quantify its capability in meeting specifications.

Other options, while valuable tools in statistical analysis, serve different purposes. Histograms are useful for visualizing the distribution of data but do not provide insights into the process's stability over time. Scatter plots help identify relationships between variables but do not analyze the variation within a process. Box plots offer a summary of data characteristics, like median and range, but do not monitor processes for control and capability in the same way that control charts do.