CONCERNING THE CORRECTNESS OF THE PRESENTATION OF THE TEST RESULTS IN THE CHEMICAL-PHARMACEUTICAL ANALYSIS

The main methodological principles and ideas of mathematical statistics on the example of their application for the correct representation of the test results in the pharmaceutical analysis are systematically outlined. The communication contains the basic concepts of error theory and an example of their calculations. The generalized rules of actions with approximate numbers are given. The theoretical material is illustrated by a number of examples and calculations, namely, the number of the exact digits of the approximate number, the limits of the reliable values of the weighted sample and the relative weighing errors, the accuracy of the weights on the given tolerances, the relative error of the rounding, the determination of the number of significant figures in the recording weight of the weighted sample, the absolute and relative error of the difference in masses and volumes, the calculation of absolute and the relative error of the determination of the moisture content, the relative error of the subordinate expression and the basis of the degree, etc. In conclusion the number of reliable decimal points (digits) of the approximate number determines its absolute error, and the number of significant digits – its relative error. The result of the measurement is rounded to the same decimal point, which is in the end of the rounded value of the reliable interval. A reliable interval should contain one or two significant digits. It was shown that in each case a general analysis of the measurement error is required, and the application of the metrological criterion of significance allows us to conclude that the measurement results are accurate. The above materials will be useful for mastering the technique of estimating the errors of measurements of physical quantities during testing in the laboratory for chemical and pharmaceutical analysis.