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.
Z Score also known as Standard Score, is the method of calculating how many standard deviations in a data set is above or below the mean. The distance between the mean and a given Z score in every normal distribution cuts off a fixed ratio of the total area below the curve. Z scores are particularly informative when the distribution to which they refer is normal.