3. The marks
scored by students in mathematics in a certain examination are given below:
Marks scored
|
1 – 20
|
21 – 40
|
41 – 60
|
61 – 80
|
81 – 100
|
Number of
students
|
3
|
8
|
19
|
18
|
6
|
Solution:
Let us make the
continuous class interval.
Marks scored
|
Extended
Class
|
Number of
students.
|
1 – 20
|
0.5 – 20.5
|
3
|
21 – 40
|
20.5 – 40.5
|
8
|
41 – 60
|
40.5 – 60.5
|
19
|
61 – 80
|
60.5 – 80.5
|
18
|
81 – 100
|
80.5 – 100.5
|
6
|
