A note on exact control limits.

This paper presents a review of the exact formulae for control limits for P charts and C charts. Also presented are appropriate graphical methods so that these limits may be easily evaluated. The use of the exact methods, given appropriate tables and/or curves, is no more difficult than the approximate methods which are prevalent in the literature. This note is not intended to criticize the approximate techniques which have been used; rather it is intended to illustrate the use of existing theory whereby the errors of approximation may be eliminated. [ABSTRACT FROM AUTHOR]