18, 17, 11, 18, 14, 14, 15, 18, 13, 12, 20, 17
Step One: Put them in numerical order.
11, 12, 13, 14, 14, 15, 17, 17, 18, 18, 18, 20
Step Two: Cross out one from each side until you are left with one or two in the center. (ones that are crossed out will be bolded for our purposes)
11, 12, 13, 14, 14, 15, 17, 17, 18, 18, 18, 20
Step Three: Since two numbers are left in the middle, the median is the number in the middle of the two.
Median = 16 (B)