A Control Chart for Thickness of Rolled-Steel Sheets Is Based $\bar { X }$

Essay

A control chart for thickness of rolled-steel sheets is based on an upper control limit of .0525 inch and a lower limit of .0475 inch. The first ten values of the quality statistic (in this case $\bar { X }$ the sample mean thickness of n =5 sample sheets) are .0508, .0495, .0504, .0503, .0514, .0500, .0487, .0502, .0507, and .0485. Comment on the behavior of this control chart.