AMOVA negative fstat


I am comparing 12 control samples with 12 treatment samples using AMOVA.

After running the test, I am getting an Fs= -0.15

p value=0.943

Is it possible to get a negative fstat? Most of the literature records fstat between 0 and 1?

Thank you

That doesn’t seem to make sense. Can you email your distance matrix and design file to Also, please include a link to this thread.


Great - thanks Pat

Just sent you a mail with design file and distance matrix attached

Kind regards