Consider the quarterly electricity production for years 1-4:
|
Year
|
1
|
2
|
3
|
4
|
|
Q1
|
99
|
120
|
139
|
160
|
|
Q2
|
88
|
108
|
127
|
148
|
|
Q3
|
93
|
111
|
131
|
150
|
|
Q4
|
111
|
130
|
152
|
170
|
(a) Estimate the trend using a centered moving average.
(b) Using an classical additive decomposition, calculate the seasonal component.
(c) Explain how you handled the end points.