1. ## Simspons Diversity Index

I have calculated the simpsons diveristy index for three different strata:
Understorey (1-D= 0.55), Subcanopy (1-D=0.77), canopy (1-D=0.83)

How can I test if there is a significant difference between these? Do I need to?

Any help would be greatly appreciated. I have had a play around in SPSS and cant seem to get anything.

Many thanks.

2. ## Re: Simspons Diversity Index

Originally Posted by deano6
How can I test if there is a significant difference between these? Do I need to?
You always need to know how certain or uncertain your numbers are. For most every day numbers you have an intuitive understanding of its variability. Imagine that you measure your length, weight or heart beat rate, once every day for a week. You know something about how much it would vary. If you had no idea if your measured length would vary a few millimeters or 100 centimeters, then the information about your length would be essentially meaningless.

I know nothing about Simpson's diversity index, so for me the numbers are meaningless. To make them meaningful for Deano6's readers she need to tell them about its standard error. Here is one text. It would cause less confusion by giving a confidence interval, then by doing a significance test.

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