1-(0.0 10+0.0 15+0.0 15+0.025+0.005)× 10= 1-0.7=0.3,

Therefore, as shown in the figure,

(2) Average score = 45× 0.1+55× 0.15+65× 0.15+75× 0.3+85× 0.25+95× 0.05 = 7/kloc-0.

(3) According to the meaning of the question, the number of people in the [60,70] score segment is 0.15× 60 = 9;

The number of people in [70,80] section is 0.3× 60 =18;

* 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,

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), * * 9.

∴ 。