(i) according to the frequency distribution histogram, obtaining;

The average score of mathematics competition in our school is divided into:

. x = 45×0.005× 10+55×0.0 15× 10+65×0.030× 10+75×0.025× 10+85×0.00。

(2) According to the histogram of frequency distribution, students with 80 points or above in Grade One (1) are:

60× (0.015+0.010 )×10 =15 (person),

Students with more than 90 points are: 60×0.0 10× 10=6 (person),

All possible values of x are 0, 1, 2,

Then p (x = 0) = c06c29c215 =1235, and p (x =1) = c16c19c215 =/kloc.

So they are listed as:? x？ 0 12P？ 1235? 1835 17 Mathematical expectation e (x) = 0×1235+1×1835+2×17 = 45.