说明：  主成分分析： (1) 根据指标的属性将原始数据统一趋势化 (2) 利用协方差、相关系数矩阵进行主成分分析，判断可否用第一主成分排名？
(Principal component analysis: (1) Unify and trend the original data according to the attribute of the indicator (2) Using covariance and correlation coefficient matrix for principal component analysis, can we use the first principal component ranking?)