Abstract |
The use of a drifting instrument requires that an adequately short recalibration period be chosen. After several periods, the calibration data can be used to test the adequacy of the choice. The paper discusses statistical tests of the recalibration period and applies these tests to continuous analyzers for sulfur dioxide. The paper presents two tests, a test of the second differences of the calibration sequence for normality and a test of the upper part of the spectrum for flatness. The paper illustrates these tests with two sequences each consisting of about fifty recalibrations of a sulfur dioxide analyzer. Also, the power of the tests and some approximations made in their formulation are investigated by Monte Carlo experiments. |