1. MEDIAN- A MEASURE OF
CENTRAL TENDENCY
Dr. RITUPARNA GHOSH
ASSISTANT PROFESSOR OF GEOGRAPHY
RANIGANJ GIRLS’ COLLEGE
2. MEDIAN FROM SIMPLE SERIES
• CALCULATE MEDIAN OF :
32, 22, 29, 17, 40, 26, 21
THE SERIES IS ODD I.E. ‘n’ IS 7
ARRANGE THE DATA IN ASCENDING ORDER
17, 21, 22, (26), 29, 32, 40
MEDIAN IS 26, IT IS THE MIDDLE MOST VALUE
IT CAN BE FOUND OUT BY OBSERVATION
3. MEDIAN FROM SIMPLE SERIES
• CALCULATE MEDIAN OF :
3.1, 2.6, 5.0, 4.7, 2.4, 3.9, 5.1, 3.6
THE SERIES IS EVEN I.E. ‘n’ IS 8
ARRANGE THE DATA IN ASCENDING ORDER
2.4, 2.6, 3.1, (3.6), (3.9), 4.7, 5.0, 5.1
MEDIAN = (3.6+3.9)/2 = 3.75
7. MEDIAN FROM GROUPED FREQUENCY
DISTRIBUTION
MARKS NO. OF STUDENTS
15-25 4
25-35 11
35-45 19
45-55 14
55-65 0
65-75 2
8. MEDIAN FROM GROUPED FREQUENCY
DISTRIBUTION
MARKS NO. OF STUDENTS
(f)
cf
15-25 4 4
25-35 11 15
35-45 19 34
45-55 14 48
55-65 0 48
65-75 2 50 = N
TOTAL 50 = N =Σf
9. MEDIAN FROM GROUPED FREQUENCY
DISTRIBUTION
MARKS NO. OF
STUDENTS (f)
cf
15-25 4 4
25-35 11 15
(35-45) (19) (34)
45-55 14 48
55-65 0 48
65-75 2 50 = N
TOTAL 50 = N =Σf
MEDIAN RANK=
N/2TH
OBSERVATION
= 50/2 = 25TH
OBSERVATION
MEDIAN CLASS=
(35-45)
10. • MEDIAN VALUE=
• Where,
• l= lower class boundary
• h= class width of median class
• N/2= Median Rank
• f= frequency of the median class
• C= cumulative frequency of the class preceding the median class
l = 35
h= 10
N/2= 25
f= 19
C= 15
MEDIAN =
40. 26