A Robust Control Chart for Monitoring Dispersion

Table 2

ARL₁(𝛿) for dispersion shifts in the 𝑁(0,1) distributions, for several values of the change time 𝜏.

𝜏	𝛿	𝑁(0,𝛿^2)
		MWCPM	ROBUSTD	NLREWMA
50	2.0	228	18.3	25.8
	3.0	141	7.9	12.6
	0.5	707	38.8	408.9
	0.33	769	17.1	223.7
300	2.0	73.0	10.1	10.6
	3.0	37.3	5.0	5.4
	0.5	1285	22.8	213.8
	0.33	728	15.2	36.9