Discuss the below:
Q: An analyst wants to use the ratio to moving average method to forecast a company's sales forecast the next few quarters. Beginning in quarter 4 of 04, the analyst collects the following sales data.
Estimate the seasonal index associated with quarter 4.
Centered ratio to
Time Moving Moving moving
period quarter sales average average average
1 4 76.3
2 1 110.9
103.425
3 2 129.1
112.325
4 3 97.4
115.550
5 4 111.9
110.825
6 1 123.8
110.050
7 2 110.2
103.425
8 3 94.3
116.650
9 4 85.4
120.400
10 1 176.7
128.900
11 2 125.2
12 3 128.3
Q: How to get the centered moving average, and the ratio to moving average ?