The Test Anxiety Scale: Concept and Research.

The validity and intercomparability of data in research related to medical, environmental, and geochemical health problems is of utmost concern and requires specific consideration in the development of an analytical approach. The Environmental Protection Agency/National Bureau of Standards Pilot Environmental Specimen Bank Program provides a vehicle for developing the precise and accurate determination of trace constituents in human livers. This approach, when implemented, gives specific consideration to a valid relationship between the analytical result and the true value in the sample. This is accomplished by minimizing contamination of the sample and/or loss of constituents, and by assuring representative analytical test portions. The analysis of the liver specimens is performed under strict quality control. The applied analytical techniques (atomic absorption spectrometry, isotope dilution mass spectrometry, neutron activation analysis, and voltammetry) have been verified for accuracy through the analysis of Standard Reference Materials. In addition, several elements are determined using two or three of these independent techniques. The first year of the program provided results on 31 elements including Se and Pb in 36 human livers.