Excellent test questions, not difficult but highly distinguished, 150 points of the test paper, 99% of students have 70 points of the question can not be done at all, on the 70 points are not differentiated, the college entrance examination selection is not the head of the 1%, or 5% and 10%, but need different levels to make different difficulty of the question.
Suppose the students are divided into five levels: one, two, three, four, five, the difficulty of the questions also corresponds to the five levels of difficulty, difficult, medium, easy, and easy, the first-class students will do difficult problems, and they are the top students, and the second-class level will be ordinary eugenics who will do more difficult problems, under normal circumstances, there are very few first-class and fifth-class students, and most students are between the second and fourth levels.
Suppose that the test questions with good discrimination, such as 135+ for first-class students in mathematics, 115+ for second-class ordinary eugenics, 90+ for second-class students at the third-class level, 75+ for the fourth-class level, and 75--for the fifth-class level, but if the test questions are particularly difficult, 20 points between the second-class level 115+ and the third-class level 95+, which the second-class students could do are now too difficult to do. As a result, the gap between eugenics and middle-level students no longer exists. If the difficulty is increased, even the advantage over students at the lower intermediate level will no longer exist.
Therefore, it is difficult for you and others to be difficult, and there is no situation where the test paper is too difficult and it is fair, my math is 30 points stronger than yours, and your English is 20 points higher, and I have an advantage in the overall score. However, if the math test questions are more difficult, and the difficulty of the excellent students can make questions that middle students can't do, and the difficulty is increased to the point that no one can do it, the original 30-point advantage may only be 10 points, and the original advantage becomes a disadvantage.
This great god that many people are after, that great god, the average score of the math paper is very low, or a difficult question, one person can't do it, this kind of test questions that will stump all students, does not mean that the teacher is powerful, just like giving primary school students the question of a quadratic function, it does not mean that the teacher is better than others.