Abstract
JIS Z 9004 is a single sampling inspection plan having desired operating characteristics as variables with the standard deviation unknown and single limit specified in the case of guaranteeing the lot quality represented as the fraction defective. However, this inspection plan with only a one-sided limit specified cannot be applied to cases when upper limit, lower limit and target value are specified. In addition, when a target value is specified, the lot quality should also be evaluated according to whether the quality characteristics of products in a lot are close to the target. Therefore, it is desirable that a sampling inspection plan rejects even a lot with a small fraction of defects as the lot mean deviates from the target. In this study, we propose a single sampling inspection plan utilizing variables with standard deviation unknown and upper limit, lower limit and target values specified in the case of evaluating the lot quality using both the fraction defective and deviation from the target. For various values of the fraction defective and deviation from the target, sample sizes are decided so as to warrant two types of consumer risk. Furthermore, we show the validity of the proposed inspection plan by investigating its operating characteristics with respect to deviation from the target.
