PERIOD Subcommand (PPLOT command)
PERIOD
indicates
the length of the period to be used by the SDIFF
subcommand.
- The specification on
PERIOD
indicates how many observations are in one period or season. You can specify any positive integer onPERIOD
. - The
PERIOD
subcommand is ignored if it is used without theSDIFF
subcommand. - If
PERIOD
is not specified, the periodicity that is established onTSET PERIOD
is in effect. IfTSET PERIOD
is not specified either, the periodicity that is established on theDATE
command is used. If periodicity was not established anywhere, theSDIFF
subcommand will not be executed.
Example
PPLOT VARIABLES = TICKETS
/SDIFF=1
/PERIOD=12.
- This command applies 1 degree of seasonal differencing with 12 observations per season to the variable TICKETS.