Median
The median is the number in the middle of a data set with odd numbers, and the average of the two numbers in the middle of a data set with even numbers. The median of 1, 2, 3, 4, 5, 6, 7, 8, 9 = 5. The median of 1, 2, 3, 4, 5, 6, 7, 8 = 4.5 (the average of 4+ 5).