品质检验员培训教材1.ppt

* Kaoru Ishikawa is known for “democratizing statistics.” Since statistical concepts are not that easy to grasp, he created ways for the average person to obtain knowledge in statistics. * Kaoru Ishikawa is known for “democratizing statistics.” Since statistical concepts are not that easy to grasp, he created ways for the average person to obtain knowledge in statistics. * Histograms suggest the nature of and possible improvements for physical mechanisms at work in progress. * Concentrating on reducing defects A, B and C since they make up 75% of all defects. Or focus on eliminating defect E, if defect E causes 40% of monetary loss. * You continue the process of branching off into more and more directions until every possible cause has been identified. The final result will represent a pile of all the factors relating to the effect being explored and the relationships between them. * These relationships are can be used to recognize indicator variables in organizations. * Flow charts define and analyze processes. They build a step-by-step picture of the process for analysis, discussion, or communication purposes. * By using a run chart, the organization can determine which day or days it is taking longer to deliver and can allow themselves more time for on-time delivery. * The process for developing a process chart is the same for almost all charts. The statistical computations is what makes it different and sometimes more complicated. 4.如何抽取样本？ 人工挑选取样法—由于有人的主观因素在起作用，不能正确反映整批产品的实际分布状态； 随机抽样—使构成总体的每一个个体都以同等概率出现在样本中。 随机抽样也可以在生产流程中进行。 * 5.随机抽样方法 1、简单随机抽样 常用的简单工具： 随机数表法（乱数表法） 掷骰法（适用于生产现场） 2、周期系统抽样 当对总体实行上述单纯随机抽样有困难时（如连续作业时抽样或产品为连续体时抽样），可采用一定间隔进行抽取的抽样方法。 3、分层抽样 从一个可以分成不同子批（或称作层）的检验批中，按规定的比例从不同的层中抽取样本。 Eg:当不同班组、不同设备、不同环境生产同一种产品时，由于条件的差别，产品质量可能有较大差异。这时，可采用分层按比例随机抽样。 * 转移规则的使用: 1,从正常检验转到加严检验:连续5批或不到5批中就有2批不接收,则应从下批起转到加严检验. 2,从加严检验转到正常检验:如果连续5批初次检验接收,则下批起恢复正常检验. 3,从正常转到放宽：必须符合以下三个条件（1）当前转移得分至少是30分。（2）生产稳定。（3）负责部门认为放宽可取。 4，从放宽转到正常。进行放宽检验时，如果出现