0-4 2 4-8 4 8-12 7 12 - 16 5 16-20 8 20 -24 3 24 - 28 2 28 -32 1 32 - 36 13 36 - 40 5 40 -44 3 44 - 48 3 find the median . also use ogives

Class Interval

Frequency (f)

Cumulative Frequency (CF)

0-4

2

2

4-8

4

6

8-12

7

13

12-16

5

18

16-20

8

26

20-24

3

29

24-28

2

31

28-32

1

32

32-36

13

45

36-40

5

50

40-44

3

53

44-48

3

56

 

Median = Size of th item

N = 56

Þ Median = Size of th item

      = Size of 28th item

This corresponds to 26th cumulative frequency and the median class is (20-24)

l = 20,  CF = 26,  f = 3

 

 

Ogive Method

Converting the series into Less than cumulative frequency.

 

 

Commutative Frequency (CF)

Coordinates of

Less than Ogive

Less than 4

2

(4, 2)

Less than 8

6

(8, 6)

Less than 12

13

(12, 13)

Less than 16

18

(16, 18)

Less than 20

26

(20, 26)

Less than 24

29

(24, 29)

Less than 28

31

(28, 31)

Less than 32

32

(32, 32)

Less than 36

45

(36, 45)

Less than 40

50

(40, 50)

Less than 44

53

(44, 53)

Less than 48

56

(48, 56)

 

Converting the series into More than cumulative frequency

 

 

Commutative Frequency (CF)

Coordinates of More than Ogive

More than 0

56

(4, 2)

    More than 4

54

(8, 6)

More than 8

50

(12, 13)

More than 12

43

(16, 18)

More than 16

38

(20, 26)

More than 20

30

(24, 29)

More than 24

27

(28, 31)

More than 28

25

(32, 32)

More than 32

24

(36, 45)

More than 36

11

(40, 50)

More than 40

6

(44, 53)

More than 44

3

(48, 56)

 

 

So, graphically Median is determined where both Less than Ogive and More than Ogive curves intersect each other.

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