Therefore, 0.3 10 = 0.03,
As shown in the figure: (4 points) (Find frequency (2 points) and plot 2 points)
(2) The average score is: x = 45×0. 1+55×0. 15+65×0. 15+75×0.3+85×0.25+95×0.05 = 7 1。
(3) According to the meaning of the question, the number of people in the [60,70] score segment is 0.15× 60 = 9; (7 points)
The number of people in [70,80] section is: 0.3× 60 =18; (8 points)
* Take a sample with a capacity of 6 from [60,80] students,
∴[60, 70] Select two people in the score section, which are marked as M and N respectively; [70, 80] Four people were selected from the score section and marked as A, B, C and D respectively;
Suppose two people are randomly selected from the sample, and the score segment [70,80] is the most 1 human event a,
Then the basic event space includes: (m, n), (m, a), (m, b), (m, c), (m, d), (c, d)*** 15, (10).
Then the basic events contained in event A are: (m, n), (m, a), (m, b), (m, c), (m, d), (n, a), (n, b), (n, c), (n, d) * *.
∴ p (a) = 9 15 = 35。 ( 12)