This figure enables a quick and straightforward classification of problematic produce in relation to country of origin and contaminant.
With 10 climatic regions, 14 soil regions and 11 distinct ecological regions, regional classification becomes problematic with differences in soils, topography, geology, rainfall, and plant and animal communities.
This classification is problematic if different subcellular structures segregate independently from one another.
The stability of the gene lists uncovered through supervised classification is problematic, even in studies using hundreds of samples (Ein-Dor et al, 2005; Michiels et al, 2005).
However, even then it was obvious that neat classifications were problematic, for it was known that a microbe could be attenuated in the laboratory, but virulence could be restored by passage in a host, suggesting that the same microbe could exist in pathogenic and non-pathogenic states.
Across all substances (tobacco, binge drinking, and marijuana use), higher levels of childhood conduct problems during kindergarten predicted a greater probability of classification into more problematic adolescent trajectory classes relative to less problematic classes.
The use of occupation as the only criteria in the classification was also problematic.
However, methods for including ancillary data sources, such as the use of prior probabilities in maximum likelihood classification, are often problematic in practice.
For tobacco and binge drinking models, increases in childhood conduct problems over time also predicted a greater probability of classification into more problematic classes.
The significance of these epidemiological studies is, however, limited because of the small number of participants, mostly males due to the working structure in the companies, and the problematic classification of exposure [17, 115].
