*
* Example 7/2/4 on pp 331-333
*
* The data on the file actually start in 1956. However, the file includes a
* column labeling the dates, so the DATA instruction is able to select out just
* the requested range for this example.
*
open data aus_electric.xls
calendar(m) 1980
data(format=xls,org=columns) 1980:1 1995:8 elec
*
graph(header="Figure 7-9 Australian monthly electricity production")
# elec
*
* BJIDENT with both the DIFFS and SDIFFS option will do all combinations of 0 or
* 1 regular and 0 and 1 seasonal differences.
*
@bjident(diffs=1,sdiffs=1,method=burg,number=40) elec
*
diff(sdiffs=1) elec / ds
diff(sdiffs=1,diffs=1) elec / dds
graph(header="Figure 7-10 Electricity data differenced at lag 12")
# ds
graph(header="Figure 7-11 Electricity data after seasonal and first differencing")
# dds