Abstract
The control charts are main tools of statistical surveillance of quality in production processes. Exponentially weighted moving average charts that make use of exact control limits are discussed in detail in this paper. We start by assessing the impact of the smoothing constant \(\lambda \) not only in the in-control average run length (ARL) of upper one-sided EWMA charts with exact control limits, but also in the range of the exact control limits of such charts with a common in-control ARL value (i.e. matched in-control). Based on the analytical results and on an extensive simulation study we conclude that the out-of-control ARL of matched in-control upper one-sided EWMA charts with exact control limits increases with \(\lambda \). This in turn suggests the use of \(\lambda \) values as close to the zero as possible and motivates what we called the (upper one-sided) limit chart. Its performance is extensively studied with regard to the ARL. Finally, we investigate the impact of \(\lambda \) on the ARL of EWMA charts with asymptotic control limits; the (maximum) conditional average delay is also addressed as an additional performance measure.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.