Acceptance Sampling by Variables

Many companies use attribute sampling plans at incoming, in-process, and final inspection. The common approach uses ANSI/ASQ Z1.4. There is an alternate, however, that may reduce cost. Sampling plans based on ANSI/ASQ Z1.9 can reduce cost by requiring smaller sample sizes.

Z1.9 uses measurements and their evaluation to make lot acceptance decisions. It looks complicated because the calculation techniques predate the common calculator. A simple statistical calculator eliminates the need for the seemingly involved calculations of the mean and standard deviation. Z1.9 uses information more effectively. When an inspection operation converts variables to attributes, it looses information. Basing the inspection on variables uses the information more effectively and allows smaller sample sizes. Z1.9 is an effective and efficient method for acceptance sampling that is easy to implement with a calculator or spreadsheet.

This webinar explains the methods in Z1.9 and shows how to use it in a more modern setting. Participants will learn the modern methods based on any simple statistical calculator that can provide the mean and standard deviation of a data set. Excel is also a good tool for this application.