The authors have been studying about the possibility of substitution of processing on the stage of the parts material. At the analyzation, the concurrent area of each processing was seized and the substitutable parts were selected, by using mainly Hayashi's Quantification Analysis II. There the authors noticed the necessity of transforming quantitative data into category data (qualitative data), and also that the unprepared transforming caused the analysis results to differ from the existing state. In this report, the authors invented a defining method of appropriate category range, in which the inference based on the experience of technical experts should work when we interpret the frequency in the quantitative data.