The probability that the score is not less than 80 points is: (0.026+0.0018) ×10 = 0.44.

Because the sample size is 500,

So there are 0.44×500=220 (people) with a score of not less than 80 points.

(2) According to the histogram of frequency distribution, the frequency with a score below 60 points is 0.004× 10=0.04.

So the qualified rate is P= 1-0.004× 10=96%.

The pass rate of instant assessment test is 96%.

(3) The average score is the sum of the areas of each small rectangle multiplied by the abscissa of the midpoint at the bottom of each small rectangle.

So the average score is: 55× 0.004×10+65× 0.020×/kloc-0+75× 0.032×10+85× 0.026×10+95× 0.

So it is estimated that the average score of this evaluation test is 78.4.