A rejection of the null hypothesis means that either the centroid and/or the spread of the objects is different between the groups.
Hence the test is based on the prior calculation of the distance between any two objects included in the experiment.
PERMANOVA shares some resemblance to ANOVA where they both measure the sum-of-squares within and between groups, and make use of F test to compare within-group to between-group variance.
However, while ANOVA bases the significance of the result on assumption of normality, PERMANOVA draws tests for significance by comparing the actual F test result to that gained from random permutations of the objects between the groups.
Finally, the PERMANOVA procedure draws significance for the actual F statistic by performing multiple permutations of the data.
The P-value is then calculated by: PERMANOVA is widely used in the field of ecology and is implemented in several software packages including the PERMANOVA[2] software, PRIMER and R (programming language) Vegan, lmPerm[3] and Python (programming language) skbio[4] packages.