All Shewhart charts have the following characteristics: Each point represents a summary statistic computed from a sample of measurements of a quality characteristic. For example, the summary statistic ...

The Shewhart chart is named after Walter A. Shewhart (1891-1967), a physicist at the Bell Telephone Laboratories, who introduced the method in 1924 and elaborated upon it in his book Economic Control ...

Control charts that are properly constructed and maintained prevent false out-of-control signals and provide a useful method for monitoring a process. Process control is and has been an important ...

Ensuring the quality and performance of human immunodeficiency virus, type 1 (HIV-1) enzyme-linked immunosorbent assay (ELISA) testing in routine laboratory situations is an important practical ...