<s>
Permutational	O
multivariate	B-General_Concept
analysis	B-General_Concept
of	I-General_Concept
variance	I-General_Concept
(	O
PERMANOVA	B-General_Concept
)	O
,	O
is	O
a	O
non-parametric	B-General_Concept
multivariate	B-General_Concept
statistical	O
permutation	B-General_Concept
test	I-General_Concept
.	O
</s>
<s>
PERMANOVA	B-General_Concept
is	O
used	O
to	O
compare	O
groups	O
of	O
objects	O
and	O
test	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
that	O
the	O
centroids	O
and	O
dispersion	O
of	O
the	O
groups	O
as	O
defined	O
by	O
measure	O
space	O
are	O
equivalent	O
for	O
all	O
groups	O
.	O
</s>
<s>
A	O
rejection	O
of	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
means	O
that	O
either	O
the	O
centroid	O
and/or	O
the	O
spread	O
of	O
the	O
objects	O
is	O
different	O
between	O
the	O
groups	O
.	O
</s>
<s>
PERMANOVA	B-General_Concept
shares	O
some	O
resemblance	O
to	O
ANOVA	B-General_Concept
where	O
they	O
both	O
measure	O
the	O
sum-of-squares	O
within	O
and	O
between	O
group	O
and	O
make	O
use	O
of	O
F	B-General_Concept
test	I-General_Concept
to	O
compare	O
within-group	O
to	O
between-group	O
variance	O
.	O
</s>
<s>
However	O
,	O
while	O
ANOVA	B-General_Concept
bases	O
the	O
significance	B-General_Concept
of	O
the	O
result	O
on	O
assumption	O
of	O
normality	O
,	O
PERMANOVA	B-General_Concept
draws	O
tests	O
for	O
significance	B-General_Concept
by	O
comparing	O
the	O
actual	O
F	B-General_Concept
test	I-General_Concept
result	O
to	O
that	O
gained	O
from	O
random	O
permutations	O
of	O
the	O
objects	O
between	O
the	O
groups	O
.	O
</s>
<s>
Moreover	O
,	O
whilst	O
PERMANOVA	B-General_Concept
tests	O
for	O
similarity	O
based	O
on	O
a	O
chosen	O
distance	O
measure	O
,	O
ANOVA	B-General_Concept
tests	O
for	O
similarity	O
of	O
the	O
group	O
averages	O
.	O
</s>
<s>
Finally	O
,	O
the	O
PERMANOVA	B-General_Concept
procedure	O
draws	O
significance	B-General_Concept
for	O
the	O
actual	O
F	B-General_Concept
statistic	I-General_Concept
by	O
performing	O
multiple	O
permutations	O
of	O
the	O
data	O
.	O
</s>
<s>
For	O
each	O
such	O
permutation	O
of	O
the	O
data	O
the	O
permutation	O
F	B-General_Concept
statistic	I-General_Concept
is	O
calculated	O
.	O
</s>
<s>
Where	O
is	O
the	O
F	B-General_Concept
statistic	I-General_Concept
obtained	O
from	O
the	O
original	O
data	O
and	O
is	O
a	O
permutation	O
F	B-General_Concept
statistic	I-General_Concept
.	O
</s>
<s>
PERMANOVA	B-General_Concept
is	O
widely	O
used	O
in	O
the	O
field	O
of	O
ecology	O
and	O
is	O
implemented	O
in	O
several	O
software	O
packages	O
including	O
PERMANOVA	B-General_Concept
software	O
,	O
PRIMER	B-Algorithm
and	O
R	B-Language
(	O
programming	O
language	O
)	O
Vegan	O
and	O
lmPerm	O
packages	O
.	O
</s>
