258
Yander Wiel
ARL ARL
50 100 500 1 5 10
M M
Figurę 7. Optimal ARLs among 4 classes of monitoring schemes. CUSUMs dominate the other schemes and the Shewhart individuals chart is only competitive for random walks (k = 1). Each curve shows the minimum ARL that can be achieved for various values of n subject to ARL0 = 500.