八字须 发表于 2009-2-19 14:24:00

如何计算UCL 和 LCL

假如每天对400个库存控制记录的出错情况进行计数,连续20天,每天出现的错误记录所占的百分比依次是:
0.0025 , 0.0075, 0.0050, 0.0150, 0.0125, 0.0075,0.0050, 0.0025, 0.0175,0.0200 ,
0.0150,0.0050, 0.0150, 0.0125, 0.0075, 0.0150, 0.0200,0.0125, 0.0075, 0.010
μ=(0.0025+0.0075+ 。。。。+0.0075+0.010)/20=0.01075
UCL=μ+3σ
LCL =μ-3σ
我的问题是σ 要怎么算出来,请哪位有空的话,帮忙解答下。谢谢

landy24 发表于 2009-2-21 17:58:00

帮你顶一下,着实看不懂。。。。
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