 The harmonic mean can be expressed as the reciprocal of the arithmetic mean of the reciprocals of the given set of observations.As a simple example, the harmonic mean of 1, 4, and 4 is

The harmonic mean "H" of the positive real numbers
formula_2 is defined to be

The third formula in the above equation expresses the harmonic mean as the reciprocal of the arithmetic mean of the reciprocals.From the following formula