Which function finds the middle value that has as many values above it in the group as are below it?

There are two math terms that find a middle value; one is the mean, or average. The formula for mean is ∑x / n. The other type of center to a set of data is the median. The median has no single formula for all situations.

The mean formula is less complicated than it looks. The "∑x" stands for the sum of all of the numbers in a set. The "n" stands for the number of data pieces in the set. So, if a certain data set was comprised of 1, 2, 3, 4, 5, the numbers should first be added together. Then the answer, in this case 15, is divided by how many numbers are in the set. There are 5 numbers in the set, so the operation would divide 15 by 5. The average of that set of numbers is 5. The median, on the other hand, finds the data piece in the middle of the data set, but not the exact average. For example, in the set 1, 2, 3, 4, 5, the median is 3. This is because there are two data pieces on either side, putting the number 3 in the center.