Thinking of solving problems: only ask for the average value, the sum of data, and then divide by the total; Finding the median depends first on whether the total number of relevant data is odd or even. The total number of students in this question is 20, even, so we should look at the scores of students 10 and 1 10 from small to large, and then find their average. The mode is the number that appears the most. You just need to find the one with the largest number of people in each grade.

The average value is [50× 2+60× 3+70× 6+80× 7+90× 2/2+3+6+7+2] = 72 (minutes);

80 points in the list corresponds to the largest number of people, so the mode of this set of data should be 80 (points);

Since the total number of people is an even number of 20, the data of 10 and 1 1 are both 70 points, so the median of this set of data should be 70 points.

1 In a math knowledge contest, the scores of 20 students in a class are shown in the following table:

achievement

(Unit: Minute) 50 60 70 80 90 students 2 3 6 7 2 Find the mode, median and average of these students' grades respectively.