Stichprobenprüfungen

Stichprobenprüfungen, also known as sampling inspections or acceptance sampling, are a method used in quality control and assurance to assess the quality of a batch of products or materials by examining only a subset of the items rather than the entire population. The fundamental principle is that if a representative sample meets certain quality criteria, the entire batch is deemed acceptable. Conversely, if the sample fails to meet these criteria, the batch is rejected or subjected to further scrutiny.

The process typically involves defining the lot size, the sample size, and the acceptable quality level (AQL). Various sampling plans exist, such as single sampling, double sampling, and multiple sampling, each with different procedures for accepting or rejecting a lot based on the number of defects found in the sample. The choice of sampling plan depends on factors like the cost of inspection, the risk of accepting defective items, and the risk of rejecting good items.

Stichprobenprüfungen are widely employed in manufacturing, pharmaceuticals, food processing, and other industries where 100% inspection is impractical or too costly. While efficient, they do carry a risk of making incorrect decisions. There is always a possibility of accepting a defective lot (Type II error) or rejecting a good lot (Type I error). Therefore, the effectiveness of stichprobenprüfungen relies heavily on the proper selection of the sampling plan and the assurance that the sample is truly representative of the entire batch.