Comparing The Effectiveness of a90/95 Calculations (Preprint)

摘要

Most practitioners see a90/95 as a static, single-point summary of an entire inspection's capability. It purports to be the size of the target having at least 90% probability of detection in 95 of 100 probability of detection (POD) experiments under nominally identical conditions. But in some situations the actual coverage is closer to 80%, rather than 95%, with 50% coverage being the median POD(a) curve itself. This paper discusses the two philosophies, the Wald Method, and the Loglikelihood Ratio Method, for constructing lower bounds on POD(a) curves (and therefore determining a90/95) and compares the effectiveness of each as functions of other experimental realities such as sample size and balance.