<s>
In	O
statistics	O
,	O
when	O
performing	O
multiple	B-General_Concept
comparisons	I-General_Concept
,	O
a	O
false	O
positive	O
ratio	O
(	O
also	O
known	O
as	O
fall-out	O
or	O
false	O
alarm	O
ratio	O
)	O
is	O
the	O
probability	O
of	O
falsely	O
rejecting	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
for	O
a	O
particular	O
test	O
.	O
</s>
<s>
The	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
is	O
calculated	O
as	O
the	O
ratio	O
between	O
the	O
number	O
of	O
negative	O
events	O
wrongly	O
categorized	O
as	O
positive	O
(	O
false	O
positives	O
)	O
and	O
the	O
total	O
number	O
of	O
actual	O
negative	O
events	O
(	O
regardless	O
of	O
classification	O
)	O
.	O
</s>
<s>
The	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
(	O
or	O
"	O
false	O
alarm	O
rate	O
"	O
)	O
usually	O
refers	O
to	O
the	O
expectancy	O
of	O
the	O
false	O
positive	O
ratio	O
.	O
</s>
<s>
The	O
level	O
of	O
significance	O
that	O
is	O
used	O
to	O
test	O
each	O
hypothesis	O
is	O
set	O
based	O
on	O
the	O
form	O
of	O
inference	O
(	O
simultaneous	B-General_Concept
inference	I-General_Concept
vs.	O
selective	O
inference	O
)	O
and	O
its	O
supporting	O
criteria	O
(	O
for	O
example	O
FWER	O
or	O
FDR	B-General_Concept
)	O
,	O
that	O
were	O
pre-determined	O
by	O
the	O
researcher	O
.	O
</s>
<s>
When	O
performing	O
multiple	B-General_Concept
comparisons	I-General_Concept
in	O
a	O
statistical	O
framework	O
such	O
as	O
above	O
,	O
the	O
false	O
positive	O
ratio	O
(	O
also	O
known	O
as	O
the	O
false	O
alarm	O
ratio	O
,	O
as	O
opposed	O
to	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
/	O
false	O
alarm	O
rate	O
)	O
usually	O
refers	O
to	O
the	O
probability	O
of	O
falsely	O
rejecting	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
for	O
a	O
particular	O
test	O
.	O
</s>
<s>
The	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
(	O
or	O
"	O
false	O
alarm	O
rate	O
"	O
)	O
usually	O
refers	O
to	O
the	O
expectancy	O
of	O
the	O
false	O
positive	O
ratio	O
,	O
expressed	O
by	O
.	O
</s>
<s>
It	O
is	O
worth	O
noticing	O
that	O
the	O
two	O
definitions	O
(	O
"	O
false	O
positive	O
ratio	O
"	O
/	O
"	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
"	O
)	O
are	O
somewhat	O
interchangeable	O
.	O
</s>
<s>
While	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
is	O
mathematically	O
equal	O
to	O
the	O
type	O
I	O
error	O
rate	O
,	O
it	O
is	O
viewed	O
as	O
a	O
separate	O
term	O
for	O
the	O
following	O
reasons	O
:	O
</s>
<s>
The	O
type	O
I	O
error	O
rate	O
is	O
often	O
associated	O
with	O
the	O
a-priori	O
setting	O
of	O
the	O
significance	B-General_Concept
level	I-General_Concept
by	O
the	O
researcher	O
:	O
the	O
significance	B-General_Concept
level	I-General_Concept
represents	O
an	O
acceptable	O
error	O
rate	O
considering	O
that	O
all	O
null	B-General_Concept
hypotheses	I-General_Concept
are	O
true	O
(	O
the	O
"	O
global	O
null	O
"	O
hypothesis	O
)	O
.	O
</s>
<s>
The	O
choice	O
of	O
a	O
significance	B-General_Concept
level	I-General_Concept
may	O
thus	O
be	O
somewhat	O
arbitrary	O
(	O
i.e.	O
</s>
<s>
As	O
opposed	O
to	O
that	O
,	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
is	O
associated	O
with	O
a	O
post-prior	O
result	O
,	O
which	O
is	O
the	O
expected	O
number	O
of	O
false	O
positives	O
divided	O
by	O
the	O
total	O
number	O
of	O
hypotheses	O
under	O
the	O
real	O
combination	O
of	O
true	O
and	O
non-true	O
null	B-General_Concept
hypotheses	I-General_Concept
(	O
disregarding	O
the	O
"	O
global	O
null	O
"	O
hypothesis	O
)	O
.	O
</s>
<s>
Since	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
is	O
a	O
parameter	O
that	O
is	O
not	O
controlled	O
by	O
the	O
researcher	O
,	O
it	O
cannot	O
be	O
identified	O
with	O
the	O
significance	B-General_Concept
level	I-General_Concept
.	O
</s>
<s>
Moreover	O
,	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
is	O
usually	O
used	O
regarding	O
a	O
medical	O
test	O
or	O
diagnostic	O
device	O
(	O
i.e.	O
</s>
<s>
"	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
of	O
a	O
certain	O
diagnostic	O
device	O
is	O
1%	O
"	O
)	O
,	O
while	O
type	O
I	O
error	O
is	O
a	O
term	O
associated	O
with	O
statistical	O
tests	O
,	O
where	O
the	O
meaning	O
of	O
the	O
word	O
"	O
positive	O
"	O
is	O
not	O
as	O
clear	O
(	O
i.e.	O
</s>
<s>
The	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
should	O
also	O
not	O
be	O
confused	O
with	O
the	O
family-wise	O
error	O
rate	O
,	O
which	O
is	O
defined	O
as	O
.	O
</s>
<s>
As	O
the	O
number	O
of	O
tests	O
grows	O
,	O
the	O
familywise	O
error	O
rate	O
usually	O
converges	O
to	O
1	O
while	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
remains	O
fixed	O
.	O
</s>
<s>
Lastly	O
,	O
it	O
is	O
important	O
to	O
note	O
the	O
profound	O
difference	O
between	O
the	O
false	B-General_Concept
positive	I-General_Concept
rate	I-General_Concept
and	O
the	O
false	B-General_Concept
discovery	I-General_Concept
rate	I-General_Concept
:	O
while	O
the	O
first	O
is	O
defined	O
as	O
,	O
the	O
second	O
is	O
defined	O
as	O
.	O
</s>
