“…It is known that for the scientific substantiation of quality there have been applied models that pertain to mathematical statistics (e.g., Isaic-Maniu & Vodă, 2008), the probability theory (e.g., Bucur & Blaj, 2011), the information theory (e.g., Dinu, 2007), fuzzy systems (e.g., Gogoncea, 2007;Marasini, Quatto, & Ripamonti, 2016), graphic methods (e.g., IsaicManiu & Vodă, 2006a), time series (e.g., Boşcaiu & Vodă, 2008), operational research (Bucur & Oprean, 2014;Ionescu, Cazan, & Negruşa, 1999) and algebraic and numerical methods (e.g., Bucur, 2013Bucur, , 2014aBucur, , 2014bDamasio da Silva, Batista, & Dumke de Medeiros, 2014;Militaru, 2008;Oprean & Bucur, 2012, 2013, 2015Petrescu & Vodă, 2009;Ţîţu & Bucur, 2016;Vodă, 2008;Neelaveni & Manimaran, 2016).…”