<s>
In	O
probability	O
theory	O
and	O
statistics	O
,	O
the	O
geometric	B-General_Concept
standard	I-General_Concept
deviation	I-General_Concept
(	O
GSD	O
)	O
describes	O
how	O
spread	O
out	O
are	O
a	O
set	O
of	O
numbers	O
whose	O
preferred	O
average	O
is	O
the	O
geometric	O
mean	O
.	O
</s>
<s>
For	O
such	O
data	O
,	O
it	O
may	O
be	O
preferred	O
to	O
the	O
more	O
usual	O
standard	B-General_Concept
deviation	I-General_Concept
.	O
</s>
<s>
Note	O
that	O
unlike	O
the	O
usual	O
arithmetic	O
standard	B-General_Concept
deviation	I-General_Concept
,	O
the	O
geometric	B-General_Concept
standard	I-General_Concept
deviation	I-General_Concept
is	O
a	O
multiplicative	O
factor	O
,	O
and	O
thus	O
is	O
dimensionless	O
,	O
rather	O
than	O
having	O
the	O
same	O
dimension	O
as	O
the	O
input	O
values	O
.	O
</s>
<s>
Thus	O
,	O
the	O
geometric	B-General_Concept
standard	I-General_Concept
deviation	I-General_Concept
may	O
be	O
more	O
appropriately	O
called	O
geometric	O
SD	O
factor	O
.	O
</s>
<s>
The	O
geometric	B-General_Concept
standard	I-General_Concept
deviation	I-General_Concept
is	O
used	O
as	O
a	O
measure	O
of	O
log-normal	O
dispersion	O
analogously	O
to	O
the	O
geometric	O
mean	O
.	O
</s>
<s>
geometric	B-General_Concept
standard	I-General_Concept
deviation	I-General_Concept
is	O
the	O
exponentiated	O
value	O
of	O
the	O
standard	B-General_Concept
deviation	I-General_Concept
of	O
the	O
log-transformed	O
values	O
,	O
i.e.	O
</s>
<s>
data	O
from	O
a	O
log-normally	O
distributed	O
population	O
may	O
be	O
used	O
to	O
find	O
the	O
bounds	O
of	O
confidence	O
intervals	O
analogously	O
to	O
the	O
way	O
the	O
arithmetic	O
mean	O
and	O
standard	B-General_Concept
deviation	I-General_Concept
are	O
used	O
to	O
bound	O
confidence	O
intervals	O
for	O
a	O
normal	O
distribution	O
.	O
</s>
