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How to find the Median Value

It's the middle number in a sorted list.

To find the Median, place the numbers you are given in value order and find the middle number.

Look at these numbers:

3, 13, 7, 5, 21, 23, 39, 23, 40, 23, 14, 12, 56, 23, 29


If we put those numbers in order we have:

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 39, 40, 56

There are fifteen numbers. Our middle number will be the eighth number:

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 39, 40, 56

The median value of this set of numbers is 23.

(Note that it didn't matter if we had some numbers the same in the list)


BUT, if there are an even amount of numbers things are slightly different.

In that case we need to find the middle pair of numbers, and then find the the value that would be half way between them. This is easily done by adding them together and dividing by two.

An example will help:

3, 13, 7, 5, 21, 23, 23, 40, 23, 14, 12, 56, 23, 29

If we put those numbers in order we have:

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 40, 56

There are now fourteen numbers and so we don't have just one middle number, we have a pair of middle numbers:

3, 5, 7, 12, 13, 14, 21, 23, 23, 23, 23, 29, 40, 56

In this example the middle numbers are 21 and 23.

To find the value half-way between them, add them together and divide by 2:

21 + 23 = 44
44 ÷ 2 = 22

And, so, the Median in this example is 22.