Median. Returns the median for a metric. The median is the number in the middle of a set of numbers. The function is created by ordering all data points and picking out the one in the middle (or if there are two middle numbers, taking the mean of those two numbers). Example: The median of 4, 1, and 7 is 4 because when the numbers are put in order (1, 4, 7), the number 4 is in the middle.