General Dynamics, Inc. is
a manufacturer of hydraulic machine tools. It has had a history of leakage
trouble resulting from a certain fitting. 25 samples of machined parts were
selected, one per shift, and the diameter of the fitting was measured.
a) Construct a X-bar
and R chars for the data provided in the following Excel file.
b) What do you think
of the results?
c) If the regular
machine operator was absent when sample 4, 8, 14 and 22 were taken, how will
the results in part b be affected?
d) A second table in
the worksheet represents measurement taken during the next ten shifts, after
the operator was back. What information does this table provide to the quality
control manager?
X-Bar and R Chart for General Dynamics
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