自相关性习题及答案 下载本文

Yt?104.985?0.669Xt

练习题7参考解答:(略) 练习题8参考解答:

(1)进口需求模型为

???2356 Y.6920?0.2883Xt t

Se = (785.1308) (0.0285) t = (-3.0017) (10.1307) 2R = 0.8875,F = 102.6305,d f = 13,DW = 0.6307

样本量n=15、一个解释变量的模型、1%显著水平,查DW统计表可知,dL=0.811, dU= 1.054,模型中DW

??0.8264 et= 0.8264 et-1 ,?令 Yt*?Yt?0.8264需Yt?1, Xt*?Xt?0.8264Xt?1, 因为n=15, 样本容量较小,采用普莱斯—温斯腾变换补充第一个观测值。

*?2?7101.43,Y1*?Y11???2?921.74。Yt*对Xt*回归,得 X1?X11??*?*??1450Y.2050?0.4587Xtt

Se?(651.9315) (0.0953) t = (-2.2245) (4.8153)

R2 = 0.6408 F = 23.1871 d f = 13 DW = 1.2873

模型中DW = 1.2873> dU,说明广义差分模型中已无自相关。

???1450.2050??8353.7154 ?11?0.8264最终的进口需求模型为 Y t = -835.7154+0.4587 X t