Calculation of Median in Individual Series | Formula of Median
Last Updated :
17 Aug, 2023
What is Median?
When elements in the data set are organised sequentially, that is, in either an ascending or descending order of magnitude, the median can be referred to as the middle value of the data set. Its value locates in a distribution in such a way that 50% of the items are below it and 50% are above it. It focuses on the center or middle of a distribution.
What is Individual Series?
The series in which the items are listed singly is known as Individual Series. In simple terms, a separate value of the measurement is given to each item.
Example of Individual Series
If the marks of 5 students of Class XI is given individually as, 70, 82, 65, 95, and 90; then, the resultant series will be an individual series.
Median in Individual Series
The steps required to determine median of an individual series are as follows:
Step 1: Firstly, arrange the given data in ascending or descending order.
Step 2: Apply the following formula of Median:
![Median(M)=Size~of~[\frac{N+1}{2}]^{th}~item](https://www.geeksforgeeks.org/wp-content/ql-cache/quicklatex.com-f8722b5befbf655ec5e3b3aaec7a8e78_l3.png "Rendered by QuickLaTeX.com")
Where,
N is the Number of Items
Median in case of Odd and Even Number of Items
In case of odd number of items, Median is the Middle term of the observation. However, in case of even number of items, the Median is the average of two middle terms and is determined by using the following formula:
![Median(M)=\frac{Size~of~[\frac{N}{2}]^{th}~item+Size~of~[\frac{N}{2}+1]^{th}~item}{2}](https://www.geeksforgeeks.org/wp-content/ql-cache/quicklatex.com-b80d42373fc4eea846b382e45f52796d_l3.png "Rendered by QuickLaTeX.com")
Example 1:
In a football game, 10 players scored the following number of goals: 4, 1, 2, 6, 10, 8, 11, 3, 9, 7.
Find the median of the data.
Solution:
Data provided: 4, 1, 2, 6, 10, 8, 11, 3, 9, 7.
Now sort the information into the following ascending order: 1, 2, 3, 4, 6, 7, 8, 9, 10, 11.
There are 10 observations in this case, which is an even number.
![Median(M)=Size~of~[\frac{10+1}{2}]^{th}~item](https://www.geeksforgeeks.org/wp-content/ql-cache/quicklatex.com-705ad150cf3b0702d7ddb60b4b3aeede_l3.png "Rendered by QuickLaTeX.com")
Median = Size of 5.5th term
To find the median, add the 5th and 6th items together and then divide the sum by 2.
Median = 6.5
Example 2:
Calculate the median of 9, 17, 13, 30, 18, 25, and 20. Find the new median if the number 13 is replaced with the number 31.
Solution:
Arrange the given data in ascending order, 9, 13, 17, 18, 20, 25, 30.
There are 7 observations, which is an odd number.
![Median(M)=Size~of~[\frac{7+1}{2}]^{th}~item](https://www.geeksforgeeks.org/wp-content/ql-cache/quicklatex.com-d8b50e7d0b5f2c8a16c886c22903fa38_l3.png "Rendered by QuickLaTeX.com")
Median = Size of 4th observation
Median = 18
When 13 is replaced by 31, the following data is obtained when arranged in ascending order: 9, 17, 18, 20, 25, 30, 31.
Now,
Median = Size of 4th observation
Median = 20
Example 3:
Find the median monthly income of 12 families provided below.
Solution:
![Median(M)=Size~of~[\frac{12+1}{2}]^{th}~item](https://www.geeksforgeeks.org/wp-content/ql-cache/quicklatex.com-7fab280340010be58f62e6be46e57a7d_l3.png "Rendered by QuickLaTeX.com")
= Size of 6.5th item
To find the median, add the 6th and 7th items together and then divide the sum by 2.
Median = 1,850
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