<s>
In	O
statistics	O
,	O
a	O
variational	B-General_Concept
series	I-General_Concept
is	O
a	O
non-decreasing	O
sequence	O
composed	O
from	O
an	O
initial	O
series	O
of	O
independent	O
and	O
identically	O
distributed	O
random	O
variables	O
.	O
</s>
<s>
The	O
members	O
of	O
the	O
variational	B-General_Concept
series	I-General_Concept
form	O
order	B-General_Concept
statistics	I-General_Concept
,	O
which	O
form	O
the	O
basis	O
for	O
nonparametric	B-General_Concept
statistical	I-General_Concept
methods	I-General_Concept
.	O
</s>
<s>
is	O
called	O
the	O
kth	O
order	B-General_Concept
statistic	I-General_Concept
,	O
while	O
the	O
values	O
and	O
(	O
the	O
1st	O
and	O
th	O
order	B-General_Concept
statistics	I-General_Concept
,	O
respectively	O
)	O
are	O
referred	O
to	O
as	O
the	O
extremal	O
terms	O
.	O
</s>
<s>
The	O
sample	B-General_Concept
range	I-General_Concept
is	O
given	O
by	O
,	O
and	O
the	O
sample	O
median	O
by	O
when	O
is	O
odd	O
and	O
when	O
is	O
even	O
.	O
</s>
<s>
The	O
variational	B-General_Concept
series	I-General_Concept
serves	O
to	O
construct	O
the	O
empirical	B-General_Concept
distribution	I-General_Concept
function	I-General_Concept
,	O
where	O
is	O
the	O
number	O
of	O
members	O
of	O
the	O
series	O
which	O
are	O
less	O
than	O
.	O
</s>
