Application of Variance Analysis to Compare Characteristics of Various Types of Hard Coal

Abstract

In Polish nomenclature many types and subtypes of coal can be found which differ between themselves by individual characteristics. However, it is often that is no easy to recognize them properly on the basis on, for example, chosen numerical data describing their features. In the paper, the variance analysis was used as the tool of comparing analysis for three chosen types of coal which were collected from three various hard coal mines located in Upper Silesia. There were coals of type 31, 34.2 and 35. Each of coals was first screened and then additionally divided into density fractions by means of zinc chloride aqueous solution. Such prepared material was then investigated because of several chosen features, like combustion heat, ash contents, sulfur contents, volatile parts contents and moisture. Together with mass it gave seven–dimensional vector describing each of chosen fractions for all three types of coals. Then, the full variance analysis was conducted with investigation of all assumptions required to its conduction. The results served to elaborate conclusions.