<s>
Seasonal	B-Application
subseries	I-Application
plots	I-Application
are	O
a	O
graphical	O
tool	O
to	O
visualize	O
and	O
detect	O
seasonality	O
in	O
a	O
time	O
series	O
.	O
</s>
<s>
Seasonal	B-Application
subseries	I-Application
plots	I-Application
involves	O
the	O
extraction	O
of	O
the	O
seasons	O
from	O
a	O
time	O
series	O
into	O
a	O
subseries	O
.	O
</s>
<s>
Seasonal	B-Application
subseries	I-Application
plots	I-Application
enables	O
the	O
underlying	O
seasonal	O
pattern	O
to	O
be	O
seen	O
clearly	O
,	O
and	O
also	O
shows	O
the	O
changes	O
in	O
seasonality	O
over	O
time	O
.	O
</s>
<s>
If	O
the	O
period	O
is	O
not	O
known	O
,	O
an	O
autocorrelation	B-Application
plot	I-Application
or	O
spectral	O
plot	O
can	O
be	O
used	O
to	O
determine	O
it	O
.	O
</s>
<s>
If	O
there	O
is	O
a	O
large	O
number	O
of	O
observations	O
,	O
then	O
a	O
box	B-Application
plot	I-Application
may	O
be	O
preferable	O
.	O
</s>
<s>
The	O
seasonal	B-Application
subseries	I-Application
plot	I-Application
is	O
an	O
excellent	O
tool	O
for	O
determining	O
if	O
there	O
is	O
a	O
seasonal	O
pattern	O
.	O
</s>
<s>
The	O
seasonal	B-Application
subseries	I-Application
plot	I-Application
can	O
provide	O
answers	O
to	O
the	O
following	O
questions	O
:	O
</s>
<s>
Practically	O
,	O
seasonal	B-Application
subseries	I-Application
plots	I-Application
are	O
often	O
inspected	O
as	O
a	O
preliminary	O
screening	O
tool	O
.	O
</s>
<s>
Seasonal	B-Application
subseries	I-Application
plots	I-Application
can	O
be	O
implemented	O
in	O
the	O
R	B-Language
programming	I-Language
language	I-Language
using	O
function	O
monthplot( )	O
.	O
</s>
<s>
The	O
following	O
R	B-Language
code	I-Language
results	O
in	O
the	O
above	O
seasonal	O
deviation	O
plot	O
of	O
antidiabetic	O
drug	O
sales	O
;	O
</s>
