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1. What is Median?
It is a measure of Central tendency.
It appears as a “middle value” in order
series
It is said to be “positional Average” in
which ‘position’ refers to place of value in
series.
Thus, median is the central value of no.
of observations in the given series

2. Computation of Median:
Individual Series
Discrete Series
Continuous Series
Continuous Series:
• In a continuous series, values are associated with
frequencies.
• The given data can be grouped in form of discrete
frequency distribution or continuous frequency
distribution.

3. Steps in calculation of median by continuous series:
Step1: Find the Cumulative frequencies.
Cumulative Frequency (Cf): The cumulative frequency
of a class is the sum of the frequency of the class and the
frequencies of the previous or above classes which is nothing but
adding of all frequencies till the required class.
Step 2: find (N/2)
Step 3: Check the cumulative frequency of value first greater than
(N/2). Then the corresponding class interval is called as Median
Class.

4. Step 4: apply the following formula
Median=L+ [(N/2)-(p.c.f) /f]*i
Where,
L1 = Lower limit of the Median Class
p.c.f = preceding cumulative frequency to the
median class
f = frequency of median class
I = the class interval of median class

5. Problem
Solution:
Calculation of median:

6. Median = size of (N/2)th observation
= (204/2) item
= 102th item
Hence the median class lies between 40-50
Median = L+ [(N/2)-(p.c.f) /f]*i
= 40+[(102-82)/30]*10
= 46.67
Where,
L1 = Lower limit of the Median Class = 40
p.c.f = preceding cumulative frequency to the
median class = 82
f = frequency of median class = 30
I = the class interval of median class =10