DOUBLE LIMIT AND RUN CONTROL CHARTS: EXACT STATISTICAL PROPERTIES

摘要

In the economic control of manufacturing processes there are two stages in the implementation of the statistical control concept. On the initiation of a process (or its re¬newal after a long shut down) the operation of statistical control is undertaken inorder to bring the process into a state of statistical stability. We use the phrase statisti-cal control in a dynamic sense when considering the steps in the procedure of bringing about the desired state and statis¬tical stability when referring to the attained state which we wish to maintain. Once the process has been judged to be in a desired state of statistical stability, further use of the statistical control concept is as a monitoring device in order to maintain the achieved state of statistical stabil¬ity.