Colloquium   RSS

Manuel Cabral Morais 03/06/2019, 16:00 — 17:00 — Abreu Faro Amphitheatre
, Instituto Superior Técnico, CEMAT - Universidade de Lisboa

On ARL-unbiased Control Charts

A control chart is a graphical device used to monitor a parameter of a measurable characteristic. An observation of the plotted control statistic beyond the control limits suggests a change in the parameter being monitored. The control limits of most charts tend to be set ignoring the skewness character of the control statistic and this may dramatically affect their average run length (ARL) performance. We derive several ARL-unbiased control charts whose ARL profiles attain a pre-specified maximum when the parameter is on-target. R is used to provide striking illustrations of how ARL-unbiased charts work in practice.


The Mathematics Colloquium is a series of monthly talks organized by the Department of Mathematics of IST, aiming to be a forum for the presentation of mathematical ideas or ideas about Mathematics. The Colloquium welcomes the participation of faculty, researchers and undergraduate or graduate students, of IST or other institutions, and is seen as an opportunity of bringing together and fostering the building up of ideas in an informal atmosphere.

Organizers: Conceição Amado, Lina Oliveira e Maria João Borges.