Science and Education Publishing World Journal of Chemical Education 2375-1657 4 2 2016 6 18 An Exercise in Sampling: The Effect of Sample Size and Number of Samples on Sampling Error 45 48 EN Juan M. Sanchez Department of Chemistry, University of Girona, 17003-Girona, Spain WJCE2016423 10.12691/wjce-4-2-3 2016 1 16 2016 5 25 2016 6 16 A simple and fast exercise is outlined to show science students the importance of determining the size of a sample and also the quantity of sample in order to minimize sampling error and improve accuracy, and to achieve a desired error.