All Shewhart charts have the following characteristics: Each point represents a summary statistic computed from a sample of measurements of a quality characteristic. For example, the summary statistic ...

Shewhart charts are broadly classified according to the type of data analyzed. Shewhart charts for variables are used when the quality characteristic of a process is measured on a continuous scale.

On May 16, 1924, Shewhart wrote an internal memo introducing the concept of the control chart as a tool for distinguishing between the two causes of variation. Around that time, Shewhart’s work ...