# Index Of Dispersion Calculator

The index of dispersion is a measure used to find whether the set of observed data are dispersed or clustered. If the mean to variance ratio calculation is equal to zero then it is not dispersed. If the mean is above one then the data is over dispersed and if the mean value is between zero and one then it is under dispersed. Enter the values of mean and variance in the below Index of Dispersion calculator to find the index of dispersion and interpretation.

## Mean to Variance Ratio Calculation

The index of dispersion is a measure used to find whether the set of observed data are dispersed or clustered. If the mean to variance ratio calculation is equal to zero then it is not dispersed. If the mean is above one then the data is over dispersed and if the mean value is between zero and one then it is under dispersed. Enter the values of mean and variance in the below Index of Dispersion calculator to find the index of dispersion and interpretation.

Code to add this calci to your website  #### Formula:

Index of Dispersion = σ2 / μ Where, μ = Mean σ2 = Variance

### Example:

In an observed set of data, the mean is 20 and the variance found is 100. Calculate the Index of Dispersion and the Interpretation.

#### Solution:

Index of Dispersion = 100/20
= 5
Since the Index of Dispersion is above one then the interpretation is overdispersed.