The exact u chart can be obtained using simple adjustments

Statistics and Probability Letters - Tập 37 - Trang 357-365 - 1998
Gemai Chen1, Smiley W. Cheng2
1Department of Mathematics and Statistics, University of Regina, Regina, Saskatchewan, Canada S4S 0A2
2Department of Statistics, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2

Tài liệu tham khảo

Anscombe, 1948, The transformation of Poisson, binomial, and negative binomial data, Biometrika, 35, 246, 10.1093/biomet/35.3-4.246 DeVor, 1992 Johnson, 1970 Quesenberry, 1991, SPC charts for a Poisson parameter λ short or long runs, J. Quality Technol., 23, 296, 10.1080/00224065.1991.11979345 Quesenberry, 1995, On properties of Poisson charts for attributes, J. Quality Technol., 27, 293, 10.1080/00224065.1995.11979609 Winterbottom, 1993, Simple adjustments to improve control limits on attribute charts, Quality Reliability Eng. Internat., 9, 105, 10.1002/qre.4680090207