Abstract
Composite samples are formed by physically mixing aliquots of individual samples. If aliquots of equal volumes are used, then the composite sample values are simply the arithmetic averages of individual sample values. If aliquots are not equal in volume, then statistical techniques need to be adjusted to account for unequal volumes. In this case, the composite sample values are weighted averages of individual sample values. The weights associated with individual sample values are proportional to the volumes of aliquots of the respective individual samples. If volumes of the aliquots are known, so that the weights also are known, then they can be treated as constants. The statistical properties of the composite sample values follow rather easily from those of the individual sample values. However, it can be the case that the volumes of the aliquots are unknown because they have resulted from a random process. In such a case, the statistical properties of the composite sample values depend not only on those of the individual sample values but also on those of the volumes (or, equivalently, of the weights) and are affected by the interrelationships between the individual sample values and the volumes of the aliquots.
*Deceased
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Bibliography
Brown, G. H. and Fisher, N. I. (1972). Subsampling a mixture of sampled material. Technometrics 14:663–668.
Cameron, D. R., Nyborg, M., Toogood, J. A., and Laverty, D. H. (1971). Accuracy of field sampling for soil tests. Can. J. Soil Sci. 51:165–175.
Carter, R. E. and Lowe, L. E. (1986). Lateral variability of forest floor properties under second-growth Douglas-fir stands and the usefulness of composite sampling techniques. Can. J. For. Res. 16:1128–1132.
Elder, R. S. (1977). Properties of composite sampling procedures. Ph.D. Dissertation. Virginia Polytechnic Institute and State University, Blacksburg, VA.
Elder, R. S., Thompson, W. O., and Myers, R. H. (1980). Properties of composite sampling procedures. Technometrics 22:179–186.
Fabius, J. (1973). Two characterizations of the dirichlet distribution. Ann. Stat. 1:583–587.
Harris, D. J. and Keffer, W. J. (1974). Waste water sampling methodologies and flow measurement techniques. Technical Report 907/9-74-005, U.S. Environmental Protection Agency.
Huibregtse, K. R. and Moser, J. H. (1976). Handbook for sampling and sample preservation of water and wastewater. Technical Report Number 600/4-76-049, U.S. Environmental Protection Agency.
Kratochvil, B. and Taylor, J. K. (1981). Sampling for chemical analysis. Anal. Chem. 53:924–938.
Rohde, C. A. (1976). Composite sampling. Biometrics 32:273–282.
Schaeffer, D. J., Kerster, H. W., Bauer, D. R., Rees, K., and McCormick, S. (1983). Composite samples overestimate waste loads. J. Water Pollut. Control Fed. 55:1387–1392.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Copyright information
© 2011 Springer Science+Business Media, LLC
About this chapter
Cite this chapter
Patil, G.P., Gore, S.D., Taillie*, C. (2011). Composite Sampling with Random Weights. In: Composite Sampling. Environmental and Ecological Statistics, vol 4. Springer, Boston, MA. https://doi.org/10.1007/978-1-4419-7628-4_7
Download citation
DOI: https://doi.org/10.1007/978-1-4419-7628-4_7
Published:
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4419-7627-7
Online ISBN: 978-1-4419-7628-4
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)