Median is the middle value for your set of data. There are two situations to look at.
1. If we have an odd number of observations, our median will be one of our observations. We put the data in order and cut off the minimum and maximum values. We continue doing this with the remaining data until the median remains.
1 2 3 3 5
Cut off 1 and 5
2 3 3
Cut off 2 and 3
3 remains, therefore our median
2. If we have an even number of observations, our median may or may not be one of our observations. We do the same process of cutting max and mins off, but we will end up with two values remaining. We then take the mean of these two values
1 2 3 4 5 6
cut off 1 and 6
2 3 4 5
cut off 2 and 5
3 4 remains, find the mean, 3.5 is our median