The comparison of two types of whitenization weight function

According to the linear relationship between the measuring data of Yangtze river, the index weight is decided by mean-variance method, triangle whitenization weight function and trapezoid whitenization weight function are established respectively to make grey evaluation for the present situation of water pollution of Yangtze river, finally the expectation results are approximate. This explains that whitenization weight function has bigger flexibility, subjectivity.