# Simpson

*.simpson

These files give the classic Simpson Index of diversity.

$H_{Simpson} = \frac {\sum_{i=1}^{S_{obs}} {S_i \left ( S_i - 1 \right )}}{N \left( N-1 \right )}$

For the Amazonian dataset, the Simpson Index is 0.0044.

Example calculations below will be performed using data from the 70.fn.shared file with an OTU definition of 0.03.