Although cusum charts and Shewhart charts are both used to detect shifts in the process mean, there are important differences in the two methods. Each point on a Shewhart chart is based on information ...

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 ...

However, the validity of these rules holds when the fundamental assumptions underlying the classical Shewhart control charts are met. Otherwise, applying traditional statistical process control (SPC) ...

Control charts for monitoring the process mean μ and process standard deviation σ are often based on samples of n > 1 observations, but in many applications individual observations are used (n = 1).