11.1 The following table contains data for consumers’ non-durables expenditure in the UK, in constant 2003 prices. Q1 Q2 Q3 Q4 1999 – – 153 888 160 187 2000 152 684 155 977 160 564 164 437 2001 156 325 160 069 165 651 171 281 2002 161 733 167 128 171 224 176 748 2003 165 903 172 040 176 448 182 769 2004 171 913 178 308 182 480 188 733 2005 175 174 180 723 184 345 191 763 2006 177 421 183 785 187 770 196 761 2007 183 376 188 955 – –

(a) Graph the series and comment upon any apparent seasonal pattern. Why does it occur?

(b) Use the method of centred moving averages to find the trend values for 2000–2006.

(c) Use the moving average figures to find the seasonal factors for each quarter (use the multiplicative model).

(d) By approximately how much does expenditure normally increase in the fourth quarter?

(e) Use the seasonal factors to obtain the seasonally adjusted series for non-durable expenditure.

(f) Were retailers happy or unhappy at Christmas in 2000? How about 2006?