Analysis and study for grade turned to score in graded system

In assessment system,for reducing the influence of the teacher's subjective factor,we turn the grade point of several teachers to quantity.The grade turned to quantity,means each grade number percentage assessed by many teachers or judges is used as area under normal distribution curve.Then,the Z value that divide equally each area namely median,is regarded as each grade result of quantity.Practice proves the method can better compare learner with the control degree of the knowledge or technical ability.The method can also be used for other grade aspects extensively.