“…Recent studies have evaluated the performance of control charts, in both phase I and II, when the parameters are unknown, proposed in order to establish new procedures to improve the performance of these charts and thus minimize α (type I error) and β risks (type II error) (Chen, 1997;Jones et al, 2001;Epprecht et al, 2005;Chakraborti & Human, 2006;Chakraborti, 2006;Castagliola et al, 2009;Costa et al, 2009;Ozsan et al, 2009;Costa et al, 2010;Trovato et al, 2010;Zhang & Castagliola, 2010;Boone & Chakraborti, 2011;Castagliola & Maravelakis, 2011;Costa & Machado, 2011;Zhang et al, 2011;Castagliola & Wu, 2012;Lee, 2013).…”