When data consist of percentages, ratios, growth rates, or other rates of change, the geometric mean is a useful measure of central tendency. For n data values,
Geometric mean = n√ product of the n data values,
assuming all data values are positive
To find the average growth factor over 5 years of an investment in a mutual fund with growth rates of 10% the first year, 12% the second year, 14.8% the third year, 3.8% the fourth year, and 6% the fifth year, take the geometric mean of 1.10, 1.12, 1.148, 1.038, and 1.16. Find the average growth factor of this investment.