Publication date: 04/12/2021

OC Curves for Acceptance Sampling Options

For attributes acceptance sampling, you can use OC curves to explore how sampling plans and assumed product quality impact the probability of accepting a lot. Use the text boxes, sliders, or fraction defective handle on the OC curve to set and adjust your sampling plan.

Single Sampling OC Curve Options

Sampling Type

Enables you to select Lot Sampling or Binomial Sampling.

Lot Sampling

Enables you to specify and explore an acceptance plan based on a fixed lot size.

Binomial Sampling

Enables you to specify and explore an acceptance plan for a continuous process or other situation where the binomial distribution is appropriate.

Lot size (N)

(Available only for Lot Sampling.) Specifies the size of the lot that you are sampling from.

Sample Size (n)

Specifies the number of units for inspection.

Acceptable failures (c1)

specifies the number of allowable failures. If the number of observed defects is greater than c1, then the lot is rejected.

Fraction Defective

Specifies the expected fraction defective in the lot.

Probability of Acceptance

Specifies the probability of accepting the lot given the sampling plan as defined. The Probability of Acceptance updates as the specifications are changed, but you can also adjust this value directly. When you adjust the Probability of Acceptance directly, the Fraction Defective value is updated.

Double Sampling OC Curve Options

First Sample

Contains the following specifications for the first sample:

Number inspected (n1)

Specifies the number of units inspected in the first sample.

Acceptable failures (c1)

specifies the number of allowable failures in the first sample.

Second Sample

Contains the following specifications for the second sample:

Number inspected (n2)

Specifies the number of units inspected in the second sample.

Acceptable failures (c1+c2)

specifies the total number of allowable failures.

Fraction Defective

Specifies the expected fraction defective in the lot.

Probability of Acceptance

Specifies the probability of accepting the lot given the sampling plan as defined. The Probability of Acceptance updates as the specifications are changed, but you can also adjust this value directly. When you adjust the Probability of Acceptance directly, the Fraction Defective value is updated.

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