Aptitude test and classification of materials with class width of statistically evaluated distinction

Classification into classes of statistically evaluated distinction is an appropriate means of assigning various materials properties simply and quickly into the relevant groups of being equivalent or different. This information, however, is subject to statistical uncertainties due to the relatively small number of samples used for materials properties testing; the large variety of materials properties modify the information on possible differences. One factor to be taken into account in determining the class width is a sufficient probability by which a difference between two materials properties can be stated when the average sample data are differing by one or more class widths. For this case, formulas for determining the required class widths, derived by a test well-known in statistical mathematics, are presented in this paper and described by numerical examples. (orig./RW)