harmonic mean

a number associated with a set of numbers, that is equal to the number of numbers divided by the sum of the reciprocals of the numbers (h = n ÷ (1/a + 1/b)) (Ex.: for , , and , h = 3 ÷ (2 + 3 + 4) = or for and , h = 2 ÷ (2 + 3) = )