748 Statistics For E Q.10.37 (a) Explain moving average method for measuring the secular trend in a time series. (b ) Calculate seasonal indices by ratio to moving average method for the following data: Quarters Years Q1 Q2 Q3 QA 2001 160 172 181 195 2002 163 186 190 207 2003 183 204 218 229 2004 210 215 235 242 Q.10.38 (a) Calculate the indices of seasonal variation by Ratio-to Mowing Average Method Years Quarters 1980 1981 1982 1983 71 72 73 71 II 72 69 80 79 III 78 75 85 81 IV 84 75 86 86 (b) Compute the indices of seasonal variation by ratio to moving average method Years Quarters 1968 1969 1970 1971 I 15.1 15.9 17.5 17.2 II 15.0 14.2 17.3 20.3 III 17.6 18.2 18.2 20.1 IV 15.4 18.3 18.7 21.6 Also find seasonal indices by link relative method. Q.10.39 (a) Discuss how seasonal indices can be calculated by ratio to trend method. (b) Construct seasonal indices by ratio to trend method. Years Quarters I II III IV 1970 125 129 114 116 1971 122 125 111 114 1972 120 111 105 100 1973 106 103 99 92