# Statistics - Harmonic Mean of Individual Series

When data is given on individual basis. Following is an example of individual series:

 Items 5 10 20 30 40 50 60 70

In case of individual items, Harmonic Mean is computed using following formula.

## Formula

$H.M. = \frac{N}{\sum (\frac{1}{X})}$

Where −

• ${H.M.}$ = Harmonic Mean

• ${N}$ = Number of observations.

• ${X}$ = Variable value

### Example

Problem Statement:

Calculate Harmonic Mean for the following individual data:

 Items 14 36 45 70 105

Solution:

Based on the given data, we have:

${x}$${\frac{1}{X}}$
140.7142
360.2777
450.0222
700.0142
1050.0095
Total1.0378

Based on the above mentioned formula, Harmonic Mean $H.M.$ will be:

$H.M. = \frac{N}{\sum (\frac{1}{X})} \\[7pt] \, = \frac{5}{1.0378} \\[7pt] \, = 4.81$

The Harmonic Mean of the given numbers is 4.81.