A Robust Control Chart for Monitoring Dispersion

Table 4

ARL₁(𝛿) for dispersion shifts in the skewed distribution 𝜒²₃, for several values of the change time 𝜏.

𝜏	𝛿	(𝜒^23−3)/√6×𝛿
		MWCPM	ROBUSTD	NLREWMA
50	2.0	149	14.4	19.7
	3.0	78.7	6.9	11.6
	0.5	624	29.1	303.2
	0.33	595	14.6	110.0
300	2.0	43.3	8.3	7.6
	3.0	24.8	5.1	5.0
	0.5	476	21.0	63.7
	0.33	229	14.3	30.0