31:T558,

Harmonic Mean

A kind of average. To find the harmonic mean of a set of n numbers, add the reciprocals of the numbers in the set, divide the sum by n, then take the reciprocal of the result. The harmonic mean of {a₁, a₂, a₃, a₄, . . ., a_n} is given below.

Harmonic Mean formula: n divided by (1/a₁ + 1/a₂ + ... + 1/aₙ). Example: numbers 4 and 9 gives 2/(1/4+1/9) = 72/13 ≈ 5.54

See also

Mean

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