Statistical Process Control Concepts(英文版)(pdf 14页)

Statistical Process Control Concepts(英文版)内容提要：
Historical Background：
Walter Shewhart (Bell Laboratories - 1920s).
1、suggested that every process exhibits some degree of variation and therefore is expected.
2、identified two types of variation (chance cause) and (assignable cause).
3、proposed first control chart to separate these
two types of variation.
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