A frequently asked question is, “What is the accuracy of the densities reported by the AccuPyc?” And that is a good question. The problem is that, though the AccuPyc reports the skeletal density of the sample under test, it actually determines the skeletal volume, V, of the test portion. It uses the sample mass, M, entered by the user, to calculate the density, ρ.
This means that the uncertainty, or error, in the density is going to be a combination of the uncertainty in the mass of the sample determined using a balance and the uncertainty of the volume determined using the AccuPyc. Actually the relative uncertainty, ερ, in the density will equal the sum of the relative uncertainty in the volume, εV, and the relative uncertainty in the mass, εM. Note that it is the relative uncertainties that are additive, not the absolute uncertainties.
A frequently asked question is, “What is the accuracy of the densities reported by the AccuPyc?” And that is a good question. The problem is that, though the AccuPyc reports the skeletal density of the sample under test, it actually determines the skeletal volume, V, of the test portion. It uses the sample mass, M, entered by the user, to calculate the density, ρ.
This means that the uncertainty, or error, in the density is going to be a combination of the uncertainty in the mass of the sample determined using a balance and the uncertainty of the volume determined using the AccuPyc. Actually the relative uncertainty, ερ, in the density will equal the sum of the relative uncertainty in the volume, εV, and the relative uncertainty in the mass, εM. Note that it is the relative uncertainties that are additive, not the absolute uncertainties.
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