## Range Chart

The range chart is a graphical method for assessing repeatability.
It indicates whether the gage variability is consistent.
The ranges for each part and each operator are displayed,
as shown in Figure A.1.

**Figure A.1:** Range Chart

For example, in Table A.1 the range
for operator George, part 1 is calculated as
0.65 - 0.60 = 0.05. Similarly computed ranges are
displayed for each operator
and each part.

You should investigate out-of-control
points and deal with them before
proceeding. If you notice that one operator's
ranges are out of control, it implies that his technique
differs from the others. If all operators have some
out-of-control ranges, you might conclude that
operator technique is affecting
the measurement system and investigate the need for training.

The range chart is created with the RCHART statement of the
SHEWHART procedure. For further information, see Chapter 39, "RCHART Statement."

Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.