This paper discusses measurement precision of subjective evaluations based on visual analog scale (VAS). 30 healthy people were invited as the experiment participants. In order to analyze their subjective evaluation for measurement precision of numbers, they were requested to answer the questionnaire on VAS (3 questions). The results showing that values based on their subjective evaluation for numbers have been obtained, and they are shown by using the combination of univariate scatter plots and box-and-whisker plots.
