The marks obtained out of 100 by 80 students in a Mathematics test are grouped below:
Marks
0–10
10–20
20–30
30–40
40–50
50–60
60–70
70–80
80–90
90–100
Number of students
2
6
7
11
15
14
10
7
5
3
(a) Prepare both the ‘less than’ and the ‘more than’ cumulative frequency tables for the above distribution.
(b) Draw the ‘less than’ and ‘more than’ ogives on the same axes, choosing suitable scales.
(c) From the point of intersection of the two curves, determine the median mark.
(d) Verify the median obtained graphically by calculating it using the median formula for grouped data.