Comparison of Selected Strategies of Statistical Quality Control

The paper presents the results of a comparative analysis of the two methods of statistical quality control of products. That two methods differ from each other mainly by a way of determining a subset of products subjected to inspection. The first of the two methods, hereinafter referred to as the completely random method, is to draw a certain number of products for control of the entire products population. The second method, called the method of drawing from partitions, is a pre-split across the specific products population into smaller parts, called partitions, and then create a representation (sample) of the products subject to control by drawing the products from each partition. The main result of this study is to determine the conditions for which the effectiveness of quality control methods with drawing from partitions is not less than the efficiency of the method with fully random drawing, whereby the efficiency criterion is the likelihood of the event, consisting in the fact that there is at least one incorrect product among the drawn products. The considerations were illustrated by numerical examples, designed to compare the effectiveness of the analyzed methods of quality control.