A Robust Control Chart for Monitoring Dispersion

Table 1

Values of the threshold sequence ℎ_𝑡 corresponding to ARL₀ of 200, 500, and 1000.

𝑡	200	500	1000
21	1.920	1.922	1.924
22	2.389	2.390	2.392
23	2.571	2.825	2.827
24	2.840	2.916	2.947
25	2.853	2.982	3.173
26	2.864	3.015	3.288
27	2.875	3.057	3.309
28	2.885	3.086	3.329
29	2.895	3.114	3.348
30	2.903	3.146	3.365
40	2.972	3.255	3.474
50	3.006	3.299	3.500
60	3.020	3.322	3.521
70	3.046	3.331	3.519
80	3.042	3.339	3.535
90	3.033	3.349	3.548
100	3.036	3.350	3.543
200	3.051	3.369	3.577
300	3.074	3.384	3.579
400	3.071	3.379	3.600
500	3.089	3.357	3.588
600	3.057	3.372	3.605
700	3.052	3.373	3.578
800	3.063	3.355	3.582
900	3.080	3.361	3.599
1000	3.083	3.369	3.593