Mean

In statistics, mean has two related meanings:

Geometric mean

The geometric mean is an average that is useful for sets of numbers that are interpreted according to their product and not their sum (as is the case with the arithmetic mean). For example rates of growth.

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: ar{x} = sqrt{prod_{i=1}^n{x_i}}

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An example

An experiment yields the following data: 34,27,45,55,22,34

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To get the geometric mean

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• How many items? There are 6. Therefore n=6
• What is the product of all items? It is 1699493400.
• To get the geometric mean take the nth (the 6th) root of that product; it is 34.5451100372