Key Points X-bar and R charts are useful control charts for use with rational subgroups. X-bar measure between-sample variation. R charts measure within-sample variation. All processes vary. The ...

Control charts based on nonparametric regression are particularly useful when the in-control (IC) or out-of-control (OC) relationship is too complicated to be specified parametrically. This paper ...

Snigdhansu Chatterjee, Peihua Qiu, Distribution-Free Cumulative Sum Control Charts Using Bootstrap-Based Control Limits, The Annals of Applied Statistics, Vol. 3, No. 1 (Mar., 2009), pp. 349-369 ...