Simpsons Diversity Index Calculator

Three different numbers are all published as "Simpson's index", and this page returns all of them from one list of species counts so they cannot be confused. Enter the counts and it gives D, the chance two individuals are the same species, 1 - D, the index of diversity, and 1 / D, the reciprocal index that reads as a number of equally common species, each with the exact fraction behind it. It also shows the proportion forms built on the sum of p squared, the Shannon index in nats and bits, and both evenness measures, along with a table of the working for every species. A second action compares two samples and says plainly when Simpson and Shannon rank them in opposite orders, which they do whenever one sample carries more rare species.