Unformatted text preview: interval.
Example 3:
Age
group
(in
years)
1520
2025
2530
3035
3540
4045 Number
of women 3
7
15
21
12
6 Less than
Cumulative
frequency
3
10
25
46
58
64 More than
cumulative
frequency
64
61
54
39
18
6 (a) Less than cumulative frequency distribution table
End values upper less than Cumulative
limit
frequency
Less than 20
3
Less than 25
10
Less than 30
25
Less than 35
46
Less than 40
58
Less than 45
64
60 (b) More than cumulative frequency distribution table
End values lower
limit
15 and above
20 and above
25 and above
30 and above
35 and above
40 and above Cumulative frequency
more than
64
61
54
39
18
6 4.8.1 Conversion of cumulative frequency to simple
Frequency:
If we have only cumulative frequency ‘ either less than or
more than’ , we can convert it into simple frequencies. For example
if we have ‘ less than Cumulative frequency, we can convert this to
simple frequency by the method given below:
Class interval
‘ less than’
Simple frequency
Cumulative frequency
1520
3
3
2025
10
10 − 3 = 7
2530
25
25 − 10 = 15
3035
46
46 − 25 = 21
3540
58
58 − 46 = 12
4045
64
64 − 58 = 6
Method of converting ‘ more than’ cumulative frequency to simple
frequency is given below.
Class interval
‘ more than’
Simple frequency
Cumulative frequency
1520
64
64 − 61 = 3
2025
61
61 − 54 = 7
2530
54
54 −39 = 15
3035
39
39 − 18 = 21
3540
18
18 − 6 = 12
4045
6
6−0 = 6
61 4.9 Cumulative percentage Frequency table:
Instead of cumulative frequency, if cumulative percentages
are given, the distribution is called cumulative percentage
frequency distribution. We can form this table either by converting
the frequencies into percentages and then cumulate it or we can
convert the given cumulative frequency into percentages.
Example 4:
Income (in Rs ) No. of
Cumulative
Cumulative
family
frequency
percentage
20004000
8
8
5.7
40006000
15
23
16.4
60008000
27
50
35.7
800010000
44
94
67.1
1000012000
31
125
89.3
1200014000
12
137
97.9
1400020000
3
140
100.0
Total
140
4.10 Bivariate frequency distribution:
In the previous sections, we de...
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 Winter '08
 Moshiri
 Business, Statistics

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