Hallo Martin,
von Zeit zu Zeit schaue ich mal ins Forum. Besser eine späte Antwort als keine...
Die Formel 0,4 * Wurzel(N) kommt aus dem Pharma-Bereich und ist als "p plan" bekannt. Hier ein Auszug aus WHO-Compendium:
The "p plan" may be used when the material is uniform, is received from a recognized source and the main purpose is to test for identity. The p plan is based on the formula p = 0.4√N, where N is the number of sampling units. The figures for p are obtained by rounding up to the next highest integer. According to this plan, samples are taken from each of the N sampling units of the consignment and placed in separate sample containers. These original samples are transferred to the control laboratory, visually inspected and tested for identity (a simplified method may be used). If the results are concordant, p final samples are formed by appropriate pooling of the original samples.
Daneben gibt's noch weitere Pläne wie z.B. den r Plan:
The
