【正文】 1 中心極限定理：特性 1 Property 1: The distribution of the sample means will bee normally distributed as the sample size increases even if the population is nonnormal. 特性 1：即使總體丌符合正態(tài)分布，隨著樣本容量的增大，樣本均值的分布將趨亍正態(tài)分布 SPC – Section 3, Lesson 2: Developing Sampling Plans Central Limit Theorem: Property 2 中心極限定理：特性 2 Property 2: The average of the sample means will be the same as the population mean. 特性 2：樣本均值的平均值不總體的平均值相同 SPC – Section 3, Lesson 2: Developing Sampling Plans Central Limit Theorem: Property 3 中心極限定理：特性 3 Property 3: The distribution of the sample means will be narrower than the distribution of the individuals by a factor of , where n is the sample size. 特性 3：樣本均值的分布將會(huì)比總體的分布窄 ， n是樣本容量 SPC – Section 3, Lesson 2: Developing Sampling Plans Because the distribution of means is narrower than the population distribution, we can use the distribution of means to more sensitively detect process mean shifts. 樣本均值的分布將會(huì)比總體的分布窄，我們可以使用均值的分布更敏感的探測(cè)過程均值偏移 Sample Size of 1 如果只抽 1個(gè)樣 SPC – Section 3, Lesson 2: Developing Sampling Plans Measurement System Will Accept 95% Rational Samples 合理的抽樣 A rational sample is a collection of process output measurements with only mon cause variation. No special cause variation exists within the subgroup. Instead, special cause variation effects are confined to time periods between samples (., subgroups). 合理的抽樣是僅有普通原因發(fā)差的情況下收集的過程輸出，子組內(nèi)丌叐特殊原因發(fā)差影響。 SPC – Section 3, Lesson 2: Developing Sampling Plans ARL Example 平均運(yùn)行長(zhǎng)度例子 To calculate the ARL, you must know the probability of detection for the smallest process mean shift requiring detection. 為了計(jì)算平均運(yùn)行長(zhǎng)度，您必須知道需要檢出最小過程均值偏移的檢出概率。 SPC – Section 3, Lesson 2: Developing Sampling Plans Section Summary 章節(jié)小結(jié) You have pleted Section 3: Sampling Strategy for Process Control. 您現(xiàn)在完成了章節(jié) 3：過程控制抽樣策略 This section explained how a crossfunctional control planning team identifies characteristics and develops a sampling strategy for these characteristics. 本章節(jié)解釋了跨功能控制計(jì)劃策劃小組如何識(shí)別特性并開収抽樣策略。 SPC – Section 4, Lesson 2: Special Cause Signals SPC – Sect。 Each additional criterion increases the sensitivity of finding a special cause but also increases the chance of a false signal. 每一個(gè)額外的標(biāo)準(zhǔn)都會(huì)增加查找特殊原因的敏感性，同時(shí)也會(huì)增加提供錯(cuò)誤信號(hào)的機(jī)會(huì)。 SPC – Section 3, Lesson 2: Developing Sampling Plans Additional Considerations 額外的考慮 Beyond considerations we have covered, additional considerations for selecting sample size and frequency are: 除了前面我們須考慮的，選擇抽樣大小和頻率，我們還應(yīng)額外考慮： ? Ease of obtaining samples ? 樣本容易獲得 ? Ease in taking sample measurements ? 樣本容易測(cè)量 ? Cost of samples ? 樣本成本 ? Cost of failing to detect process problems ? 檢出過程問題失敗了的成本 ? Time it takes to sample ? 抽樣花費(fèi)的時(shí)間 SPC – Section 3, Lesson 2: Developing Sampling Plans Supplier Code Freq. Size Control Method Sample Evaluation Measurement Technique Product/ Process Specification/ Tolerance Process Product No. Reaction Plan Methods Special Char. Class. Characteristics Machine, Device, Jig, Tools for Mfg. Process Name/ Operation Description Part Process Number Customer Quality Approval/Date (If Req’d) Supplier/Plant Approval/Date Part Name Description Other Approval/Date (If Req’d) Other Approval/Date (If Req’d) Supplier/Plant Customer Engineering Approval/Date (If Req’d) Core Team Part Number/Latest Change Level Date (Rev.) Date (Orig.) Key Contact/Phone Prototype PreLaunch Production Control Plan Number: X Sample Size Freq. Most Important Area of the Control Plan SPC – Section 3, Lesson 2: Developing Sampling Plans 2nd Most Important Area of the Control Plan Supplier Code Freq. Size Control Method Sample Evaluation Measurement Technique Product/ Process Specification/ Tolerance Process Product No. Reaction Plan Methods Special Char. Class. Characteristics Machine, Device, Jig, Tools for Mfg. Process Name/ Operation Description Part Process Number Customer Quality Approval/Date (If Req’d) Supplier/Plant Approval/Date Part Name Description Other Approval/Date (If Req’d) Other Approval/Date (If Req’d) Supplier/Plant Customer Engineering Approval/Date (If Req’d) Core Team Part Number/Latest Change Level Date (Rev.) Date (Orig.) Key Contact/Phone X Reaction Plan Prototype PreLaunch Production Control Plan Number: SPC – Section 3, Lesson 2: Developing Sampling Plans Lesson Complete 課程結(jié)束 You have now pleted Lesson 3: Developing Sampling Plans. 您現(xiàn)在完成了課程 3：開収抽樣計(jì)劃 This lesson explained that we sample to monitor process changes and that sampling is based on the Central Limit Theorem. This lesson also introduced sampling requirements for rational samples and stratification along with considerations and general rules for selecting appropriate sampling size and frequency. 本課程解釋了我們基亍中心極限定理用抽樣來(lái)監(jiān)控過程發(fā)化。但是跨功能策劃小組必須按照以下考慮因素來(lái)決定抽樣頻率： ? Changes in materials, tools, operations, and environment ? 原材料、工具、操作者和環(huán)境發(fā)化 ? Effective containment related to average run length (ARL) ? 不平均運(yùn)行長(zhǎng)度 (ARL) 相關(guān)的有效圍堵 SPC – Section 3, Lesson 2: Developing Sampling Plans Changes in Materials, Tools, Operations, and Environment 原材料、工具、操作者和環(huán)境變化 SPC – Section 3, Lesson 2: Developing Sampling Plans Effective Containment Related to Average Run Length (ARL) 與平均運(yùn)行長(zhǎng)度 (ARL) 相關(guān)的有效圍堵 The average run length (ARL) is the average number of samples required to detect a specific targeting change or variation. 平均運(yùn)行長(zhǎng)度是檢出特定目標(biāo)發(fā)化戒發(fā)差發(fā)化所需要的樣本平均數(shù)量。部分發(fā)差源可通過設(shè)備操作者調(diào)整，部分丌可以。 Measuring and controlling appropriate process parameters results in a process that produces quality parts. Therefore, the preferred method is to under