controlchart
A control chart is a statistical tool used in statistical process control to monitor a process over time and determine whether the process is in a state of statistical control. It plots a measured variable in time order and is centered on a process mean, with upper and lower control limits that define the expected range of natural variation. Data points outside these limits or patterns within the limits may indicate special causes or a change in the process.
There are several common chart types. X-bar and R charts monitor the mean and range of subgroups
Construction involves collecting baseline data to estimate the center line (mean) and control limits, typically set
Interpretation focuses on distinguishing common cause variation, which is inherent to the process, from special cause