What is median?
Median definition can be divided into two categories:
1. It is the middlemost number in a list having odd number of data arranged in an ascending order
2. It is the mean of the middle two numbers in a list having even number of data arranged in an ascending order
PROBLEM 1
Below is a list of marks of students in Biology quiz with 30 maximum possible mark
27 , 12 , 16 , 15 , 11
Now , let’s find the median in this set of data values
SOLUTION

To find median , we will first rearrange the data set in ascending order like this
11, 12 , 15, 16 , 27

There are 5 (odd ) number of values .

Using 1st definition of median , we find the middle number. Hence, 15 is the median here
PROBLEM 2
If the list given in Problem1 is changed like this
27 , 12 , 16 , 15 , 11, 7
Find median for this list
SOLUTION

First rearrange the list in an ascending order like this
7, 11, 12 , 15, 16 , 27

Using 2nd median definition as we have 6 (even) number of values here , we calculate median as
So , 8.5 is the median hereGENERAL FORMULA
In general , the following median formula is used for finding the median
where n is the number of values in a dataset
MODE ,MEAN,MEDIAN , RANGE
In order to have cluster analysis of large dataset , the terms range ,median ,mode ,mean are frequently used where mean , mode , median are three different measures of central tendency .Mostly , mean and median are used interchangeably but the fact is mean in contrary to median is as similar as average.
Among mean ,median ,mode and range , mode and range are quite peculiar as range is the difference between largest and smallest value while mode is the value that appears frequently.
More topics in Median  
Median Definition  How do you Find the Median 
Median Example 
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