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 z-score, also known as standard score, is a measurement used in statistics. It is the measurement of the number of standard deviations a specific number is above or below a mean. The formula to calculate z-score is. z = (x - Î¼) / Ï. where. 1  z is the z-score, 2  x is the value to be standardized,3  Î¼ is the mean of the given set of data, 4  Ï is the standard deviation of the given set of data.t is the measurement of the number of standard deviations a specific number is above or below a mean. The formula to calculate z-score is. z = (x - Î¼) / Ï. where. 1  z is the z-score, 2  x is the value to be standardized, 3  Î¼ is the mean of the given set of data,