Stuck in the Middle
The median is the middle number in an ordered data set. That is easy peasy, right? Yep, but there is always an exception **insert eyeroll here**.
Odd-Numbered Data Sets
If you have an odd number of values in your data set, then yes, middle number is easy to see:
Data set with odd number of values: 8, 89, 150, 200, 751
In the data set above, there are five numbers. The third is easy to see as the middle number as there are two numbers on each side of that number.
Even-Numbered Data Sets
Even-numbered data sets are easy too, just a little extra work involved. With even-numbered data sets, you have two middle numbers so you have to make them one number. First, put the data set in order if it isn’t already. Next, add the two middle numbers together and then, divide by 2. Does that last step sound familiar? It should because you are getting the mean of those two numbers.
Data set with even number of values before ordering: 4, 28, 12, 87
Data set with even number of values after ordering: 4, 12, 28, 87
The two numbers are 12 and 28. Now let’s add them together to get 40. Divide 40 by 2. The median for this data set is 20.