1. Calculate Class and their frequency table

X	Cumulative Frequency
0	40
10	36
20	29
30	16
40	5
50	0

Solution:
First we convert Cumulative frequency table to gropued frequency table

>	Cumulative Frequency
> 0	40
> 10	36
> 20	29
> 30	16
> 40	5
> 50	0

Class and their frequency table is

Class	Cumulative Frequency	Frequency
0 - 10	40	4 (= 40 - 36)
10 - 20	36	7 (= 36 - 29)
20 - 30	29	13 (= 29 - 16)
30 - 40	16	11 (= 16 - 5)
40 - 50	5	5 (= 5 - 0)

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2. Calculate Class and their frequency table from the following grouped data

X	Cumulative Frequency
10	4
20	11
30	24
40	35
50	40

Solution:
First we convert Cumulative frequency table to gropued frequency table

<	Cumulative Frequency
< 10	4
< 20	11
< 30	24
< 40	35
< 50	40

Class and their frequency table is

Class	Cumulative Frequency	Frequency
0 - 10	4	4 (= 4)
10 - 20	11	7 (= 11 - 4)
20 - 30	24	13 (= 24 - 11)
30 - 40	35	11 (= 35 - 24)
40 - 50	40	5 (= 40 - 35)

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