With penalties and minimum withdrawal requirements to consider, timing is of the utmost importance when taking money from your IRA. (Getty Images) Individual retirement accounts, commonly known as IRAs, are retirement fund staples for many people.
In statistics, the mean is the mathematical average of a set of numbers. The average is calculated by adding up two or more scores and dividing the total by the number of scores. Consider the following number set: 2, 4, 6, 9, 12. The average is calculated in the following manner: 2 + 4 + 6 + 9 + 12 = 33 / 5 = 6.6.
The bell then slopes down to each side; one side represents scores that are lower than the average, and the other side represents scores that are above the average. Mean: The mean is the average score. The average is calculated by adding all of the scores together, then dividing by the total number of scores. Standard Deviation: This is a measure of variability in a population. A low standard deviation means that most of the data points are very close to the same value.