What to Do with a Mean & Range Chart

The continual sampling and completing of the Mean & Range Chart should be carried out as specified in the Chart headings. As monitoring of the process continues, the data should be examined for any indication that the process is displaying signs of unexpected or changing variation.

At this early stage of the Chart's completion, in this exercise, the process would appear to be in a state of statistical control because:

• all the plots fall within the control limits
• there are no signs of an unusual pattern developing in the data.

If you find an out-of-control plot develops, you should:

• tell your team leader
• work with him or her to find the cause of the plot
• work with other people who might help
• if something is wrong, take on the "ownership" of putting it right

The Analysis and Interpretation of the plotted control charts is discussed in greater detail in another module of this course.