************************************************************************* Department of Mathematical Sciences The Johns Hopkins University SEMINAR ************************************************************************* Jiayang Sun October 26, 2000 Department of Statistics 304 Whitehead Hall Case Western Reserve University Preseminar: 3:00 p.m. Refreshments: 3:30 p.m. Seminar: 4:00 p.m. ************************************************************************* A NEW JOINT CONTROL CHART: JOINT BEHAVIOR OF AVERAGE AND MAXIMUM OF A GENERAL PROCESS ************************************************************************* ABSTRACT Quality control is widely used in industries to monitor the quality of products in a manufacturing process. The Shewhart chart and its variants are more effective in detecting a large mean shift, while CUSUM charts are more effective in detecting a small mean shift. We propose a new joint control chart that combines the merits of Shewhart and CUSUM charts and that can deal with general processes. A process here can be correlated (stationary or nonstationary) and in high dimension. Simulations, animations, and applications will be demonstrated/discussed. The problem mentioned above is related to the joint distribution of mean-max (average and maximum) of a continuous-time process, and to the joint distribution of max-max (maxima of the process and the average process up to time t) of the process. Based on a cute geometric argument, we present general approximations to such joint distributions, which are of interest themselves. *************************************************************************