计量经济学第三版课后答案 下载本文

4.3

(1)根据Eviews分析得到数据如下: Dependent Variable: LNY Method: Least Squares Date: 12/05/14 Time: 11:39 Sample: 1985 2011 Included observations: 27

Variable Coefficient Std. Error t-Statistic Prob. LNGDP 1.338533 0.088610 15.10582 0.0000 LNCPI -0.421791 0.233295 -1.807975 0.0832 C -3.111486 0.463010 -6.720126 0.0000 R-squared 0.988051 Mean dependent var 9.484710

Adjusted R-squared 0.987055 S.D. dependent var 1.425517 S.E. of regression 0.162189 Akaike info criterion -0.695670 Sum squared resid 0.631326 Schwarz criterion -0.551689 Log likelihood 12.39155 Hannan-Quinn criter. -0.652857 F-statistic 992.2582 Durbin-Watson stat 0.522613 Prob(F-statistic) 0.000000

得到的模型方程为:

LNY=1.338533 LNGDPt-0.421791 LNCPIt-3.111486

(2)

① 该模型的可决系数为0.988051,可决系数很高,F检验值为992.2582,

明显显著。但当α=0.05时,t(24)=2.064,LNCPI的系数不显著,可能存在多重共线性。 ②得到相关系数矩阵如下: LNY LNGDP LNCPI LNY 1.000000 0.993189 0.935116 LNGDP 0.993189 1.000000 0.953740 LNCPI 0.935116 0.953740 1.000000 LNGDP, LNCPI之间的相关系数很高,证实确实存在多重共线性。

(3)由Eviews得: a)

Dependent Variable: LNY Method: Least Squares Date: 12/03/14 Time: 14:41 Sample: 1985 2011 Included observations: 27

Variable Coefficient Std. Error t-Statistic Prob. LNGDP 1.185739 0.027822 42.61933 0.0000 C -3.750670 0.312255 -12.01156 0.0000 R-squared 0.986423 Mean dependent var 9.484710

Adjusted R-squared 0.985880 S.D. dependent var 1.425517 S.E. of regression 0.169389 Akaike info criterion -0.642056 Sum squared resid 0.717312 Schwarz criterion -0.546068 Log likelihood 10.66776 Hannan-Quinn criter. -0.613514 F-statistic 1816.407 Durbin-Watson stat 0.471111 Prob(F-statistic) 0.000000

b)

Dependent Variable: LNY Method: Least Squares Date: 12/03/14 Time: 14:41 Sample: 1985 2011 Included observations: 27

Variable Coefficient Std. Error t-Statistic Prob. LNCPI 2.939295 0.222756 13.19511 0.0000 C -6.854535 1.242243 -5.517871 0.0000 R-squared 0.874442 Mean dependent var 9.484710

Adjusted R-squared 0.869419 S.D. dependent var 1.425517 S.E. of regression 0.515124 Akaike info criterion 1.582368 Sum squared resid 6.633810 Schwarz criterion 1.678356 Log likelihood -19.36196 Hannan-Quinn criter. 1.610910 F-statistic 174.1108 Durbin-Watson stat 0.137042 Prob(F-statistic) 0.000000

c)

Dependent Variable: LNGDP Method: Least Squares Date: 12/05/14 Time: 11:11 Sample: 1985 2011 Included observations: 27

Variable Coefficient Std. Error t-Statistic Prob. LNCPI 2.511022 0.158302 15.86227 0.0000 C -2.796381 0.882798 -3.167634 0.0040 R-squared 0.909621 Mean dependent var 11.16214

Adjusted R-squared 0.906005 S.D. dependent var 1.194029

S.E. of regression 0.366072 Akaike info criterion 0.899213 Sum squared resid 3.350216 Schwarz criterion 0.995201 Log likelihood -10.13938 Hannan-Quinn criter. 0.927755 F-statistic 251.6117 Durbin-Watson stat 0.099623 Prob(F-statistic) 0.000000

①得到的回归方程分别为

1)LNY=1.185739 LNGDPt-3.750670 2)LNY=2.939295 LNCPIt-6.854535 3)LNGDPt=2.511022 LNCPIt-2.796381

②对多重共线性的认识:

单方程拟合效果都很好,回归系数显著,判定系数较高,GDP和CPI对进口的显著的单一影响,在这两个变量同时引入模型时影响方向发生了改变,这只有通过相关系数的分析才能发现。

(4)建议:如果仅仅是作预测,可以不在意这种多重共线性,但如果是进行结构分析,还是应该引起注意的。

4.4

(1)按照设计的理论模型,由Eviews分析得:

Dependent Variable: CZSR Method: Least Squares Date: 12/03/14 Time: 11:40 Sample: 1985 2011 Included observations: 27

Variable Coefficient Std. Error t-Statistic CZZC 0.090114 0.044367 2.031129 GDP -0.025334 0.005069 -4.998036 SSZE 1.176894 0.062162 18.93271 C -221.8540 130.6532 -1.698038 R-squared 0.999857 Mean dependent var

Adjusted R-squared 0.999838 S.D. dependent var S.E. of regression 353.0540 Akaike info criterion Sum squared resid 2866884. Schwarz criterion Log likelihood -194.5455 Hannan-Quinn criter. F-statistic 53493.93 Durbin-Watson stat Prob(F-statistic) 0.000000

Prob. 0.0540 0.0000 0.0000 0.1030 22572.56 27739.49 14.70707 14.89905 14.76416 1.458128

从回归结果可见,可决系数为0.999857,校正的可决系数为0.999838,模型拟合的很好。F的统计量为53493.93,说明在α=0.05,水平下,回归方程回归方程整体上是显著的。但是t检验结果表明,国内生产总值对财政收入的影响显著,但回归系数的符号为负,与实际不符合。由此可得知,该方程可能存在多重共线性。

(2)得到相关系数矩阵如下: CZSR CZZC GDP SSZE CZSR 1.000000 0.998729 0.992838 0.999832 CZZC 0.998729 1.000000 0.992536 0.998575 GDP 0.992838 0.992536 1.000000 0.994370 SSZE 0.999832 0.998575 0.994370 1.000000 由上表可知,CZZC与GDP,CZZC与SSZE,GDP与SSZE之间的相关系数都非常高,说明确实存在多重共线性。

(3)做辅助回归 被解释变量 CZZC GDP SSZE 可决系数 0.997168 0.988833 0.997862 方差扩大因子 353 90 468