Attenberger J, Müller H E
Offentl Gesundheitswes. 1989 Jul;51(7):362-5.
Collaborative studies of comparative investigations of standardized drinking water were performed within Lower Saxony since two years. The results show that the precision of the measurements even in the reference laboratories is substantially less than the measuring tolerance given by the Federal Drinking Water Regulation. Therefore, the standard deviation of the different parameters, variation coefficients, respectively, are to be used for the internal statistical quality control as well as for the judgment of water. Protests against drinking water, bath water, respectively, due to parameters exceeded should be made just if the guide or imperative values are exceeded by the threefold standard deviation experimentally determined in reference laboratories.
两年来，下萨克森州开展了标准化饮用水比较调查的合作研究。结果表明，即使在参考实验室中，测量精度也远低于联邦饮用水法规规定的测量公差。因此，不同参数的标准偏差（即变异系数）应用于内部统计质量控制以及水质判断。只有当参数超过参考实验室实验确定的三倍标准偏差时，才应对饮用水、沐浴水等因参数超标而提出抗议。
