# Determine Median for even Number of Values

Question by Guest | 22.02.2014 at 20:20

Usually, you are determining the median by sorting the values according to their size and the median is just the middle value taken from this rank order.

So, as an example, given the values 5, 3, 1, 7, 2, we would sort them (1, 2, 3, 5, 7) and the median would be 3.

However, this principle is only applicable when having an odd number of values. Given an even number of values such as 1, 2, 3, 5 as an median, both, 2 and 3 are suitable.

So, what can you do in this case (except hoping that both middle values are equal)? Or is it not possible to determine a median if your sample size is not uneven? Normally, the median for an even number of values is the average (arithmetic mean) of both middle values.

So, in your case for the numbers 1, 2, 3, 5, the two middle values are 2 and 3 and the mean of them is (2+3)/2 = 2.5. And this is the median.

However, if the median has to be part of the sample/has to occur in the values, you can also determine the upper median (3 in your case) or the lower median (2 in your case) by taking the best next value from the sample. But, as I said, usually, you are just taking the mean of the two middle values.
22.02.2014 at 20:47