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How to Determine a Geometric Mean

The geometric mean defines an average value of a set of "N" numbers as the "N"-th root of the product of "N" numbers. This parameter is only readily defined for a set of positive real numbers. The geometric mean formula can efficiently reduce an effect of very large or small outlier numbers on the average set value. Hence, in some cases, geometric mean provides better weighted values than the arithmetic mean.

Things You'll Need

Scientific calculator
Microsoft Excel

Instructions

Using a calculator
- 1
  Calculate the product of all numbers in the set. For example, the product of the numbers 10, 4.13, 17, 5 and 31 is 10 x 4.13 x 17 x 5 x 31 = 108825.5.
- 2
  Divide "1" by the size of the number set. In the example, the set consists of five numbers; 1 / 5 = 0.2.
  .
- 3
  Enter the product from Step 1 in the calculator, press the key "X^Y" and enter the value from Step 2.
- 4
  Press the "=" key to calculate the geometric mean. In the example, it is 10.17 (rounded here to the second decimal point).
In Microsoft Excel
- 5
  Start Microsoft Excel.
- 6
  Click on the cell "A1" in the spreadsheet and press "=" on the keyboard.
- 7
  Type the command "GEOMEAN(number 1, number 2,...,number_n)" and press "Enter." For example, GEOMEAN(11, 25.4, 6, 67) followed by "Enter."
- 8
  Read the geometric mean that will appear in cell "A1." In this example, it will be 18.31 (rounded here to the second decimal point).

Numerology