Meaning
Statistical inspection protocols define the maximum number of defective units permitted in a production lot for the batch to remain commercially viable. Implementation of acceptable quality limit sampling allows a buyer to accept or reject large shipments based on the results of a representative subset. This approach balances the cost of full inspection against the risk of allowing substandard components into the assembly line.
Selection Logic
Determination of the sample size depends on the total lot quantity and the required level of confidence. Standard tables provide the necessary indices to select a random group from the population.
Risk Balance
Producers face the possibility that a good lot might be rejected due to a statistical anomaly in the sample. Conversely, the consumer risks receiving a batch that contains more defects than the specified limit. These two factors dictate the strictness of the inspection plan and the economic consequences for the supplier.
Lower limits indicate a higher requirement for consistency and often result in more frequent rejections.
Acceptance Threshold
A lot passes if the count of non-conforming items falls below the limit established by the chosen quality level. If the count exceeds this number, the entire shipment is typically returned for full sorting or rework. Every decision is based on the data observed in the sample.
