For quality control charts controlling the mean of a population either small samples may be taken out at frequent intervals or larger samples at less frequent intervals. In this paper, a simple formula is derived by which the most suitable sample size can be determined, leading to the detection of any given change of the population mean with a minimum of inspection.
"On the Most Economical Sample Size for Controlling the Mean of a Population." Ann. Math. Statist. 23 (2) 247 - 254, June, 1952. https://doi.org/10.1214/aoms/1177729441