Abstract
A Statistical distribution model (dislocated lognormal distribution). which is convertible to normal distribution after transformation of the variable by log (x-a), is adopted as a model for normal range calculation. The distribution parameters are calculated from sample statistics (mean, standard deviation and skewness). The distribution conform well to non-normal and non-lognormal distributions. Calculated normal ranges are makedely affected by a few cases of abnormal data, and the method is only applicable to pure normal samples.
