Source: https://www.researchgate.net/publication/5007081_Cartas_de_control_Bayesianas_para_atributos_y_el_tamano_de_subgrupo_grande_en_la_carta_p/fulltext/0225d4210cf21f9b4787c683/Cartas-de-control-Bayesianas-para-atributos-y-el-tamano-de-subgrupo-grande-en-la-carta-p.pdf