*
* Example 1.5.5 from pp 33-34
*
open data deaths.dat
calendar(m) 1973 1 12
data(format=free,org=columns) 1973:1 1978:12 deaths
*
* You can do the seasonal difference with the DIFFERENCE instruction with the
* option SDIFFS=1 (1 seasonal difference). The span of the seasonal difference is
* taken from the CALENDAR under which you're currently working. For a
* non-consecutive differencing with some other gap, use SDIFFS=1 with SPAN=gap.
*
diff(sdiffs=1) deaths / d12
graph(footer="Figure 1-26 Seasonally Differenced Deaths")
# d12
*
* Difference the d12 series to get the series with the
* combined differencing.
*
diff d12 / d1_d12
graph(footer="Figure 1-27 Seasonally + Regular Differenced")
# d1_d12
*
* You can also do the two together on a single DIFFERENCE instruction - to do
* that, include both an SDIFFS and a DIFFS option.
*
diff(sdiffs=1,diffs=1) deaths / d1_d12