Statistical Standard
Attribute sampling procedure for quality inspection. The ansi asq z14 establishes a mathematical framework for determining batch acceptance based on the number of nonconforming units. Quality managers use these tables to set acceptable quality levels.
Sampling Plan
Sample sizes vary according to the batch quantity and the required inspection severity. An ansi asq z14 provides three levels of general inspection and four special levels for smaller sample sets. Inspectors select a plan that balances the cost of testing against the risk of accepting defective lots.
This selection dictates the quantity of units pulled from the production line.
Switching Rule
Procedural shifts occur when quality levels change over time. The ansi asq z14 requires a move to tightened inspection if two out of five consecutive batches are rejected. Conversely, if ten consecutive batches remain within limits, the protocol allows for reduced inspection.
These rules maintain a dynamic pressure on the supplier to maintain standards.
Risk Boundary
Operating characteristics determine the probability of accepting a batch at a specific defect rate. The ansi asq z14 defines the producer risk of rejecting a good lot and the consumer risk of accepting a bad one. Manufacturers verify these risks by plotting curves that show the relationship between defect density and acceptance probability.
Correct application of the standard prevents the release of substandard electronics to the market.
