harmonic mean

n. An average calculated by taking the reciprocal of the arithmetic mean of the reciprocals of a group of numbers. Thus the harmonic mean of 1, 2, and 3 is equal to

\(\frac{1}{1}+\frac{1}{2}+\frac{1}{3}=\frac{1.8333}{3}=.6111, \frac{1}{.6111}=1.636\)