A graphical method was developed for the statistical evaluation of the results of metabolic tests; this method affords evaluation with due respect to the variance of characters in selected sets and the size of the tested group of animals. In principle, the method is based on the determination of the arithmetical mean and a 95% confidence interval of the selective mean of the values for each parameter of biochemism in each group of animals; these values are then expressed as per cent with regard to a mean reference value. Graphical comparison is enabled for both score and interval estimation of the distribution of a character in the studied group of animals, with a reference interval and reference mean.