Abstract: It is easy to determine the supremum of the population standard deviation or coefficient of variation for the material to be tested although to find the standard deviation or coefficient of variation is difficult by means of the information from data-base before the test begins.On the basis of the fact, the methods of supremum of population standard deviation and coefficient of variation are presented for test design and statistical analysis of the result. The one-sided lower confidence limits of the population percentiles obtained by the methods are greater than that by the one-sided tolerance factor at a given confidence level, the number of specimens requires fewer.

Key words: supremum of standard deviation, supremum of variation coefficient, population percentile, one-sided lower confidence limit