趋势比率法

某企业2006-2008年各季度的利润额资料如表所示，试预测2009年个季度的利润额；

某企业利润额及趋势比率法计算表利润额Yt趋势值Tt剔除趋势值，St~123456710111241252937503332446240445531.230833.007034.783236.559438.335740.111941.888143.6345.4407.216848.993050.76921.31280.75740.83371.01211.30430.82270.76391.00771.340.84720.811.0833单位：万元季节指数Yt^1.32630.80860.83141.03371.32630.80860.83141.03371.32630.80860.83141.033741.422226.688728.918637.791650.845632.433634.825545.135960.269038.178540.732552.4803年、季2006 12342007 12342008 1234平均值预测：2009 1234t1314151652.5454554.3216856.097957.874131.32630.80860.83141.033769.692443.923346.639559.8246季节指数计算表季节指数200620072008求和1234合计1.31280.75740.83371.30430.82270.76391.340.84720.813.98152.42732.4958平均值（剔除随机）1.3271650.809090.831921最终季节指数1.3263250.8085780.8313941.01211.00771.08333.10311.034357074.0025341.0006331.033702349万元|Yt-Yt^|/Yt0.01030.06750.00280.02140.01690.01720.08830.02580.02790.04550.07430.04580.0370①计算趋势线，设为Yt=a^=b^tYt=29.4545+1.7762t;年、季t利润额Ytt*Ytt^22006 1141411222550433298794437148162007 15502502526331983637322244948443522008 196255881210404001003114448412141255660144合计784923452650平均值6.541b^=1.776224a^=

29.45455