Control chart |Types| x̅ and R chart

What is control chart

The control chart is the fundamental tool of statistical process control, as it indicates the range of variability that is built into a system (known as common cause variation).


It helps to determine whether or not a process is operating consistently or if a special cause has occurred to change the process mean or variance.


The control chart have a centre line that represents the average value of the quality characteristic corresponding to the in-control state.Two other horizontal lines, called the upper control limit (UCL) and the lower control limit (LCL).


→Control Chart in 7QC tool is a type of run chart used for studying the process variation.