If the group of numbers is given, then Median is the middle number of the group when they are ranked in order.
If there are an even number in the group, the mean of the middle two is taken.

How to find Median

To find the median of the group of numbers:

order the list according to its elements value.

Then repeatedly remove the pair consisting of the smallest and biggest numbers until either one or two values are left.

If exactly one number is left, this is the Median.

If two values left, Median is the arithmetic mean of these two.

Example 1.
Calculate Median of the group of numbers {1, 7, 3, 13}.

First, we should order the group: {1, 3, 7, 13}.
Then we have to remove the pair of smallest and highest numbers to obtain the list {3, 7}.
Since there are two elements in this remaining list, Median is equal to Arithmetic mean, (3 + 7)/2 = 5.

Example 2.
Calculate Median of the group of numbers {3, 3, 4}.

The group is already ordered.
Then the first 3 and the last 4 are removed, and only number 3 is remained.
So, Median is 3.