Geometric mean

Another measure of central tendency that is important in business and economics, but often overlooked, is the geometric mean. Business analysts  and economists who are interested in growth over a number of time periods use the geometric mean. Applications of the geometric mean in finance include compound interest over several years, total sales growth, and population growth. An important question concerns the average growth each year that will result in a certain total growth over several years.
The geometric mean, is the nth root of the product of n numbers:

 The geometric mean is used to obtain mean growth over several periods, given compounded growth from each period:

For example, the geometric mean of
            1.05     1.02      1.10       1.06             is