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.
A positive z-score means the data value is larger than the mean. If a data value has a z-score of 2, that tells us that this data value is 2 standard deviations larger than the mean. A negative z-score means the data value is smaller than the mean. If a data value has a z-score of â3.1, then this data value is 3.1 standard deviations smaller than the mean. A z-score of zero means that the data value equals the mean. For example, consider a data set with a mean of 50 and a standard deviation of 2. If a data value also is 50, then the z-score is: