To set X-bar chart upper and lower control limits, one must know the process central line, which is the Para establecer los limites de control superior e Interior del grfico x barra, se debe conocer la linea control del proceso, que es el O average range rango promedio total number of defects in the population nmero total de defectos en la poblacin average of the sample means promedio de las medias muestrales percent defects in the population porcentaje de defectos en la poblacin