Design of Sampling Schedules

Abstract

Concern with the statistical precision associated with certain pollutant sampling schedules led to comparison of two sampling schemes, designated as “modified random” and “systematic” sampling methods. A nearly uninterrupted body of data representing six years of sampling provided a basis from which to perform hypothetical “sampling” by the two methods. Comparison of results shows that the systematic method generally gave better results. The method is very simple; ft entails the selection of a sampling interval (other than 7 days or multiple of 7), the selection (randomly) of an initial sampling date, and regular sampling at the selected interval thereafter.