Application of Z-score to visualization and correlation of archaeological complexes

Standardization is reprocessing of data aimed at bringing it to the same format or range, for example, while comparing two archaeological collections with the number of artifacts differing by an order of magnitude. Arithmetic calculation of percentages is commonly applied to such comparisons. However, percentages are influenced by many factors. This article provides an example of identifying a specific type of spalls (bladelets with curved lateral profile) produced from specific (carinated) cores. Calculation of percentages was not suitable for comparing two different categories of artifacts from several samples because only two categories of artifacts curved bladelets and carinated cores were considered in the analysis. For calculating percentages, all categories of spalls (bladelets with curved, twisted, and straight profiles) or cores (prismatic, narrow-faced, carinated, and flat-faced) are used. Accordingly, the percentage of one type of artifacts would be influenced by the number of artifacts of other types. Thus, the percentage of bladelets with curved profiles would be influenced by the number of bladelets with straight and twisted profiles in the sample thereby significantly changing the data and affecting results of counts and correlations. In this situation, the most rational solution would be using z-score or data standardization, which does not affect the sampling structure, leaves all outliers, but brings the data to the same range. The z-score method is promising due to simplicity of its application as well as wide range ofproblems in archaeology it may solve, such as comparison of different complexes and categories of artifacts, especially including those which markedly differ in their quantitative content.