Statistical and mathematical concepts and principles applicable to uncertainty calculations for the measurement of in vivo bone lead by 109Cd K X ray fluorescence

"This work discusses the statistical and mathematical concepts and principles applicable to in vivo 109Cd K X Ray Fluorescence measurements (109Cd KXRF) of lead in human bone. The primary aim of this paper is to examine divergent views about the quantitative methods applied to estimate in vivo bone lead concentrations and their uncertainty when using the 109Cd KXRF technique. The emphasis is on the potential effect of covariance between quantities of interest on the result of an in vivo measurement of bone lead by 109Cd KXRF, a question which has received little attention in view of the long standing problem of why the average measurement uncertainty is less than the standard deviation of repeated measurements.