## Harmonic Mean of a distribution:

Harmonic Mean is the reciprocal of mean of reciprocal values in the distribution.

Harmonic Mean of the distribution is given by the formula

X_{ H} = n / ∑ (1/X_{i})

when X_{i} > 0 for i = 1,2,3......n

### Examples of Harmonic Mean:

- Cost Averaging

- Travelling a constant distance "d" by breaking the distance as

d_{1}, d_{2},...d_{n}, travelling each distance with a different velocity and finally

finding out a uniform velocity that would have required to travel the entire

distance with the same total time is nothing but finding the harmonic mean

of the velocities.

## Method Name:

harmonic_mean(data)

## Method Overview:

harmonic_mean() function from the statistics module of python standard library, returns the harmonic mean of the distribution which is also called as the subcontrary mean of the distribution.

## Example Python Program to find the Harmonic Mean of a distribution:

import statistics
# velocities of individual distances velocityData = [50,55,65,60]
# Find harmonic mean harmonicMean = statistics.harmonic_mean(velocityData)
#print the harmonic mean with a precision of upto 2 decimal points print("The harmonic mean of velocities is:%.2f"%(harmonicMean)) |

## Output of the Python Program that finds the Harmonic Mean of a distribution:

The harmonic mean of velocities is:56.95 |