and in the postal network, we need to use the pcs cause selecting control chart or p control chart to control the quality indices according as they are correlated to the quantity of exchange or not.

• 在邮政通信网部分指出,根据质量指标与交换量是否相关而分别采用p_(cs)选控图与p控制图进行控制。 本文并提出p_(cs)选控图的第一个实例。