Correct sampling

{{Short description|Sampling scenario in Gy's sampling theory}}

{{one source|date=February 2012}}

During sampling of granular materials (whether airborne, suspended in liquid, aerosol, or aggregated), correct sampling is defined in Gy's sampling theory as a sampling scenario in which all particles in a population have the same probability of ending up in the sample.

{{cite book | last=Gy | first=Pierre | title=Sampling of particulate materials : theory and practice| series=Developments in geomathematics | publisher=Elsevier Scientific Pub. Co. | publication-place=Amsterdam | date=1979 | isbn=0-444-41826-1 | oclc=5101118| url=https://books.google.com/books?id=dYIjAQAAIAAJ}}

The concentration of the property of interest in a sample can be a biased estimate for the concentration of the property of interest in the population from which the sample is drawn. Although generally non-zero, for correct sampling this bias is thought to be negligible.