Cumulative Frequency Distribution of the less type

Example: Consider the cumulative frequency distribution table as given below.


Marks
No of Students
0-10
5
10-20
3
20-30
4
30-40
3
40-50
3
50-60
4
60-70
7
70-80
9
80-90
7
90-100
8

Solution:
Find the no of students with score less than or equal to upper interval.

Marks Obtained
No of Students (f)
Cumulative frequencies (cf)
Less than 10
5
5
Less than 20
3
8
Less than 30
4
12
Less than 40
3
15
Less than 50
3
18
Less than 60
4
22
Less than 70
7
29
Less than 80
9
38
Less than 90
7
45
Less than 100
8
53


The distribution given above  is called cumulative frequency distribution of the less than type.