Acceptance Control Charts Based on the Exact and Normal Approximations to the Binomial Distribution.

摘要

Procedures are developed for finding the sample size and control limit for Acceptance Control Charts for proportion of nonconforming units using the exact binomial distribution, the standard normal approximation to the binomial, and a normalized arcsin transformation of the data. The user must select an Acceptable Process Level and a Rejectable Process Level and the associated risks for each. The approximation methods are compared to the exact method over a wide range of design specifications. It was found that the arcsin transformation is considerably more accurate than the standard normal approximation and, although more complex to figure, is preferable if the user is familiar with small scientific pocket calculators. If a microprocessor or minicomputer is available, the exact binomial may be used with ease to achieve at least the stipulated risk protection desired. FORTRAN programs for the three formulations are included. (Author)