Question :The distribution below gives the weights of 30 students of a class. Find the median weight of the students:
The correct answer :To find the median weight of the students, we need to arrange the weights in ascending order. However, the weights in the table are given in intervals, so we need to first calculate the midpoint of each interval.
Weight interval |
Midpoint |
---|---|
40-45 |
42.5 |
45-50 |
47.5 |
50-55 |
52.5 |
55-60 |
57.5 |
60-65 |
62.5 |
65-70 |
67.5 |
70-75 |
72.5 |
Next, we need to calculate the cumulative frequency of the weights, which is the sum of the number of students up to that interval.
Weight interval |
Midpoint |
Number of Students |
Cumulative Frequency |
---|---|---|---|
40-45 |
42.5 |
2 |
2 |
45-50 |
47.5 |
3 |
5 |
50-55 |
52.5 |
8 |
13 |
55-60 |
57.5 |
6 |
19 |
60-65 |
62.5 |
6 |
25 |
65-70 |
67.5 |
3 |
28 |
70-75 |
72.5 |
2 |
30 |