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Mathematics quality inspection in senior three.
(i) In stratified sampling, the probability that each person is selected is the total number of people in the sample population (2 points).

So the probability of a student being drawn is p = 1 10. (3 points)

(II) Question meaning X =1000-(60+90+300+160) = 390, (4 points)

Therefore, it is estimated that the number of students who have reached the excellent line in this middle school is m =160+390×120-1120-90 = 290 (people). (6 points)

(iii) Histogram of frequency distribution. (9 points)

The average math score of this school in this exam is. x = 60× 15+90×45+300×75+390× 105+ 160× 135 1000 = 90。 (65438

It is estimated that the average score of mathematics in this school is 90. ( 12)