The full score of a math test item is 10 and 12. The students' scores are 9, 7, 9, 9, 5, 1, 3, 9, 8, 4, 9, 2 respectively, and the difficulty coefficient of this topic is 0.625.

The difficulty coefficient reflects the difficulty of the test question, that is, the score of the candidate in a test question or a test paper. The calculation formula of the difficulty coefficient is L=X/W, where l is the difficulty coefficient, x is the average score of the sample, and w is the total score of the test paper. According to the topic, l = (9+7+9+9+5+1+3+9+8+4+9+2)/(10 *12) = 0.625.

Difficulty Purpose:

1, the difficulty level determines the screening topic. Generally speaking, the difficulty of examination should be beneficial to students' learning, but a certain degree of difficulty can increase the degree of discrimination, which is very important for fully understanding and mastering students' learning situation.

2. Pass rate should be considered when determining the difficulty level to prevent students' self-esteem.

3. The determination of the degree of difficulty should consider the influence on the score distribution, which is generally based on the positive skewed distribution, and sometimes the positive skewed distribution can stimulate students' enthusiasm for learning.