ABSTRACT

In the preceding two chapters, the decision for acceptance or rejection of a lot or process was based upon attributes, that is, counts of the number of nonconforming units or of nonconformities on the units in samples. Such an approach is always possible. For, if the quality characteristic is a measurement, such as a dimension, a weight of contents or a tensile strength, this can always be converted to an attribute by comparison to a maximum or a minimum limit, or to two limits. Thus, the measurement either lies inside limits or it does not. On the other hand, many attribute characteristics are not capable of being converted to a measurement.