Int J Performability Eng ›› 2012, Vol. 8 ›› Issue (4): 457-461.doi: 10.23940/ijpe.12.4.p457.mag

• Short Communications • Previous Articles    

A Theoretically Appropriate Poisson Process Monitor

RYAN BLACK and JUSTIN R. CHIMKA   

  1. Department of Industrial Engineering, University of Arkansas, Fayetteville, AR, USA

Abstract:

Because the probability of Type I error is not evenly distributed beyond upper and lower three-sigma limits the c chart is theoretically inappropriate for a monitor of Poisson distributed phenomena. Furthermore the normal approximation to the Poisson is of little use when c is small. These practical and theoretical concerns should motivate the computation of true error rates associated with individuals control assuming the Poisson distribution.