ABSTRACT

This chapter concerns some of the problems involved in controlling the quality of a manufactured product. It deals with acceptance sampling, which is concerned with monitoring the quality of manufactured items supplied by the manufacturer to the consumer in batches. The problem is to decide whether the batch should be accepted or rejected on the basis of a sample randomly drawn from the batch. The chapter concerns process control. The problem is to detect changes in the performance of the manufacturing process and to take appropriate action when necessary to control the process. The problem is to design a sampling plan so that batches of 'good' quality are likely to be accepted whereas batches of 'bad' quality are likely to be rejected. The major branch of statistical quality control is that of process control. The most commonly used tool for detecting changes is the control chart or Shewhart chart.