SPC Chart (X-bar/R)
In this X-bar/R chart, lot means are displayed in the bottom graph, and lot ranges are displayed in the top graph. An out of control point for lot 644 is shown as a red filled square. A time-stamped note indicates "routine maintenance". Clicking on this note causes a red vertical highlight line to be drawn at the x position (e.g., timestamp) associated with the note. Light-blue regions show reference time periods (e.g., night shifts).