Acceptance Sampling in Quality Improvement

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Average Out Going Quality (AOQL) Attributes Single Sampling Plan

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This type of sampling plan is normally used on batches or lots prior to shipping to a customer, to ensure that the outgoing quality matches the specified level for customer acceptance. Several samples are taken randomly, and the number of defectives counted. If the number of defectives exceed a certain number for that sample size the batch is rejected, and 100 percent inspection carried out. Defective items are then removed and replaced with good items ensuring....

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Average Outgoing Quality Limit (AOQL) Attributes Double Sampling Plan

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Double sampling plans generally require less sampling than single sampling plans but are more complicated to use....

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Lot Tolerance Percent Defectives (LTPD) with Rectification Double Sampling Plan

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For a double sampling plans you take a first sample consisting of n items and each item is checked to see if it is defective. The number of defective items is then counted and compared with the first sample acceptance value for the sampling plan. If the number of defectives is less or equal to the first sample acceptance value the batch is rejected....

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Lot Tolerance Percent Defectives (LTPD) with Rectification Single Sampling Plan

The BIS.Net Team The BIS.Net Team

This type of sampling plan, as is the AOQL plan, is normally used on batches, or lots prior, to shipping to a customer ensuring that the outgoing quality matches the specified level for customer acceptance. Several samples are taken randomly, and the number of defectives counted. If the number of defectives exceed a certain number for that sample size the batch is rejected, and 100 percent inspection carried out....

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Lot Tolerance Percent Defectives (LTPD) without Rectification Double Sampling Plan

The BIS.Net Team The BIS.Net Team

This type of sampling plan can be used on batches, or lots prior to shipping to a customer when rectification is not possible. For example, when testing cans of soft drink for composition, rectification is not possible because every can would have to be opened to test the composition and decide which cans needs replacing. More often the plan is used to screen incoming goods. Rejected batches are returned to the supplier....

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Lot Tolerance Percent Defectives (LTPD) without Rectification Single Sampling Plan

The BIS.Net Team The BIS.Net Team

A sampling plan consists of a sample size and acceptance value. A lot is rejected if the number of defectives in the sample size exceeds the acceptance value....

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Lot Tolerance Percent Defects (LTPD) without Rectification Sampling Plan

The BIS.Net Team The BIS.Net Team

This sampling plan must not be confused with Lot Tolerance Percent Defective sampling plans. Instead of taking a sample of n items and counting the number of defectives, a sample of n items is taken, and the number of defects counted. Rectification plans are not applicable for defects sampling plans....

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Operating Characteristic (OC) Curve for Defects sampling plans

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An OC curve is an important tool for the analyst to assess the protection a given sampling plan provides....

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Operating Characteristic (OC) Curve

The BIS.Net Team The BIS.Net Team

An OC curve is an important tool for the analyst to assess the protection a given sampling plan provides. It is not uncommon practice to set arbitrary sampling plans e.g. take a sample size of 5 and reject the batch if there are more than zero defectives. The OC Curve permits the analyst to evaluate the effectiveness of such plans....

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Variables Sampling Plan for Lot Average

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Variables acceptance sampling plans are used when quality characteristics are measured on a continuous scale. Variables sampling plans tend to be more efficient than Attributes Sampling plans with a much lower sample size....

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Variables Sampling Plan - Fraction Defectives - Standard Deviation Known

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This type of sampling plan protects against the receipt, or release of lots with excessive defectives. Defectives are items where measurements fall outside specification limits. For example moisture content may be specified for a delivery of a raw material. If the percentage of moisture that falls outside specification limits is excessive the lot will be rejected....

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Variables Sampling Plan - Fraction Defectives - Standard Deviation Unknown

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There are two types of sampling plans provided for fraction defectives plans. One is for standard deviation known and the other standard deviation unknown. This plan is used if the standard deviation is unknown....

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Qtech International has specialized in the development of quality information systems and analytic technologies for leading manufacturing corporations for 30 years in 40 countries. Our research into machine-powered algorithms has spanned over 10 years, with foundation research being university supervised prior. Research has involved many sectors, including manufacturing, health, political campaigning, retail, finance and more.

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