Methodology for Reliable Assessment of Water Quality. IV. Probability of Satisfactory Normalization and Control (Statistical Analysis, Nonparametric Approach)

Abstract

It was emphasized that the assessment of water quality by comparing its characteristics with reference values inevitably leads to the analysis of the area of ambiguity by methods of mathematical statistics. The study results of the aquatic environment are correct if presented in a standard form with indication of confidence intervals and figures. To do this, it was proposed to build a non-parametric tolerance interval that takes into account both the margin and normalized errors of the assessed water quality indicators. Examples of analysis of water quality in natural water bodies of industrial region were provided. The article describes four options for a decisive function in assessing water quality (strict acceptance, strict rejection, non-strict acceptance, non-strict rejection), the choice of which in practice should be made by the water user or contracting parties on the basis of technical features and ecological situation.