The data must follow the normal distribution.The critical to quality (CTQ) characteristic must be measurable as a real number (variables data) to (1) quantify the process standard deviation and (2) assess the assumption that the data follow a normal or bell curve distribution.
Narrow limit gauging tightens the acceptance limits and makes it possible to detect increases in the nonconforming fraction with much smaller samples.Zero acceptance sampling, a form of discovery sampling, can reduce the sample size even further but at the cost of an elevated risk of wrongly rejecting lots at the AQL.Alternatives such as double sampling, multiple sampling, and sequential sampling can decrease the average sample number (ASN) to a certain degree.A sample of 1250 is required at the best (0.01%) AQL. Traditional attribute sampling plans (ANSI/ASQ Z1.4, formerly MIL-STD 105) require very large samples as the acceptable quality level (AQL) decreases.
0 kommentar(er)
