12.1. STATISTICAL PROCESS CONTROL (SPC)
12.1.1. Types of control charts
There are two broad categories of control charts: those for use with continuous data (e.g., measurements) and those for use with attributes data (e.g., counts). This section describes the various charts used for these different data.
18.104.22.168. VARIABLE CHARTS
In statistical process control (SPC), the mean, range, and standard deviation are the statistics most often used for analyzing measurement data. Control charts are used to monitor these statistics. An out-of-control point for any of these statistics is an indication that a special cause of variation is present and that an immediate investigation should be made to identify the special cause.