Acceptance sampling

ACCEPTANCE SAMPLINGACCEPTANCE SAMPLING

Er.Sartaj.Singh.Bajwa

Acceptance Sampling Acceptance Sampling DefinedDefined

• Acceptance Sampling is a form of Acceptance Sampling is a form of inspection that is used to inspection that is used to determine whether or not goods determine whether or not goods are coherent with a set standard of are coherent with a set standard of qualityquality


Acceptance SamplingAcceptance Sampling

• Acceptance sampling is a process Acceptance sampling is a process that helps to determine whether to that helps to determine whether to accept or reject the sample being accept or reject the sample being observedobserved


Risks of Acceptance Risks of Acceptance SamplingSampling

• Producers RiskProducers Risk– The risk associated with a producer The risk associated with a producer

rejecting a lot of materials that rejecting a lot of materials that actually have good qualityactually have good quality• Also referred toAlso referred to

as a Type I Error oras a Type I Error or

((αα ) )


Risks of Acceptance Risks of Acceptance SamplingSampling

• Consumers RiskConsumers Risk– The risk associated with a consumer The risk associated with a consumer

accepting a lot of materials that accepting a lot of materials that actually have poor qualityactually have poor quality• Also referred toAlso referred to

as a Type II Error or as a Type II Error or

((ββ ) )


When can acceptance When can acceptance sampling be applied?sampling be applied?

• At any point in productionAt any point in production• The output of one stage is the input The output of one stage is the input

of the nextof the next



• Sampling at the Input stageSampling at the Input stage– Prevents goods that don’t meet Prevents goods that don’t meet

standards from entering into the standards from entering into the processprocess

– This saves rework time and moneyThis saves rework time and money



• Sampling at the Output stageSampling at the Output stage– Can reduce the risk of bad quality Can reduce the risk of bad quality

being passed on from the process to a being passed on from the process to a consumerconsumer

– This can prevent the loss of prestige, This can prevent the loss of prestige, customers, and moneycustomers, and money



• Sampling at the Process stage Sampling at the Process stage – Can help adjust the process and Can help adjust the process and

reduce the amount of poor quality in reduce the amount of poor quality in productionproduction

– Helps to determine the source of bad Helps to determine the source of bad production and enables return for production and enables return for reprocessing before any further costs reprocessing before any further costs may be incurredmay be incurred


Typical Application of Typical Application of Acceptance SamplingAcceptance Sampling

• Based on the observations made, Based on the observations made, the decision is made to either the decision is made to either accept or reject the entire accept or reject the entire shipmentshipment


Typical Application of Typical Application of Acceptance SamplingAcceptance Sampling

• The decision to accept or reject the The decision to accept or reject the shipment is based on the following shipment is based on the following set standards:set standards:– Lot size = NLot size = N– Sample size = nSample size = n– Acceptance number = cAcceptance number = c– Defective items = dDefective items = d

• If d <= c, accept lotIf d <= c, accept lot• If d > c, reject lotIf d > c, reject lot


Acceptance Sampling PlanAcceptance Sampling Plan

• Mr. Smith owns and operates a Mr. Smith owns and operates a manufacturing plant. manufacturing plant.

– He receives a shipment of 1,000 He receives a shipment of 1,000 sheets of glass. sheets of glass.

– Of the shipment, Mr. Smith chooses to Of the shipment, Mr. Smith chooses to sample 50 sheets. sample 50 sheets.


Acceptance Sampling PlanAcceptance Sampling Plan

• If more than 2 are defective, he is If more than 2 are defective, he is sending back the entire shipment sending back the entire shipment to the supplier.to the supplier.

• Mr. Smith observes 5 defective Mr. Smith observes 5 defective sheets of glass.sheets of glass.


Acceptance Sampling Plan Acceptance Sampling Plan

• Therefore, according to the set Therefore, according to the set standards mentioned above:standards mentioned above:

– N = 1,000N = 1,000– n = 50n = 50– c = 2c = 2– d = 5d = 5

– N = 1,000N = 1,000– n = 50n = 50– c = 2c = 2– d = 5d = 5



• What should Mr. Smith do in What should Mr. Smith do in reference to the number of reference to the number of defective items observed????defective items observed????



• Remember, if d > c, reject lotRemember, if d > c, reject lot• Since c = 2, and d = 5…Since c = 2, and d = 5…

– Mr. Smith should Mr. Smith should

reject the lot of reject the lot of

1,000 sheets of glass1,000 sheets of glass


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Acceptance sampling