Shewhart Control Charts for Variables

X(bar) R Control Chart

  • Control limits for X(bar) R control chart are calculated as shown below.

Calculating Control Limits for X(bar) R Control Chart

Example Graph

Shewhart X(bar) R Control Chart

Use of historical µ and σ values for calculating the control limits:

The plot options of this control chart provides the option of using sample or historical data for µ or/and σ in the computation of control limits

  • Whether a graph is plotted based on sample or historical data is differentiated by annotation on the upper X-axis of the graph.