Page 244 - DCOM203_DMGT204_QUANTITATIVE_TECHNIQUES_I

Unit 11: Analysis of Time Series

Notes
Example: Given the following quarterly sale figures, in thousand of rupees, for the year
2007-2010, find the specific seasonal indices by the method of moving averages.
Year I II III IV
2007 34 33 34 37
2008 37 35 37 39
2009 39 37 38 40
2010 42 41 42 44
Solution:
Calculation of Ratio to Moving Averages

4 Period Y
Year /Quarter Sales Centred Total 4 Period M 100
Moving Total M
2007 I 34   
II 33   
138
III 34 279 34.9 97.4
141
IV 37 284 35.5 104.2
143
2008 I 37 289 36.1 102.5
146
II 35 294 36.8 95.1
148
III 37 298 37.3 99.2
150
IV 39 302 37.8 103.2
152
2009 I 39 305 38.1 102.4
153
II 37 307 38.4 96.4
154 38.9
III 38 311 97.7
157
IV 40 318 39.8 100.5
161
2010 I 42 326 40.8 102.9
165
II 41 334 41.8 98.1
169
III 42   
IV 44   
Calculation of Seasonal Indices
Year I II III IV
2007 97.4 104.2
2008 102.5 95.1 99.2 103.2
2009 102.4 96.4 97.7 100.5
2010 102.9 98.1
Total 307.8 289.6 294.3 307.9
A
i 102.6 96.5 98.1 102.6
S.I. 102.7 96.5 98.1 102.7

399.8
Note that the Grand Average G 99.95 . Also check that the sum of indices is 400.
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