The sales data in Table 3-12 are for quarterly exports of a French company.
|
ear
|
Quarter
|
Period
|
Sales(thousands of francs)
|
Year
|
Quarter
|
Period
|
Sales(thousands of francs)
|
|
1
|
1
|
1
|
362
|
4
|
1
|
13
|
544
|
|
|
2
|
2
|
385
|
|
2
|
14
|
582
|
|
|
3
|
3
|
432
|
|
3
|
15
|
681
|
|
|
4
|
4
|
341
|
|
4
|
16
|
557
|
|
2
|
1
|
5
|
382
|
5
|
1
|
17
|
628
|
|
|
2
|
6
|
409
|
|
2
|
18
|
707
|
|
|
3
|
7
|
498
|
|
3
|
19
|
773
|
|
|
4
|
8
|
387
|
|
4
|
20
|
592
|
|
3
|
1
|
9
|
473
|
6
|
1
|
21
|
627
|
|
|
2
|
10
|
513
|
|
2
|
22
|
725
|
|
|
3
|
11
|
582
|
|
3
|
23
|
854
|
|
|
4
|
12
|
474
|
|
4
|
24
|
661
|
Table 3-12: Quarterly exports of a French company.
(a) Make a time plot of the data. Note the pronounced seasonality.
(b) Use a classical multiplicative decomposition to estimate the seasonal indices and the trend.
(c) Comment on these results and their implications for forecasting.