First put them in order
2 9 27 34 38 49 53 55
Pick the number in the middle
In this case there is not one in the middle, there are two so you have to average the two.
(34 + 38)/2 = 36
2 9 27 34 38 49 53 55
Pick the number in the middle
In this case there is not one in the middle, there are two so you have to average the two.
(34 + 38)/2 = 36