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计量经济学第七章第5,6,7题答案

第7章练习5解:根据Eview 软件得如下表:Dependent Variable: YMethod: ML - Binary Logit (Quadratic hill climbing) Date: 05/22/11 Time: 22:19Sample: 1 16Included observations: 16Convergence achieved after 5 iterationsCovariance matrix computed using second derivativesVariableCoefficientStd. Error z-StatisticProb.??C Q VMcFadden R-squared ????Mean dependent var . dependent var ????. of regression Akaike info criterion ????Sum squared resid Schwarz criterion ????Log likelihood Hannan-Quinn criter. ????Restr. log likelihood LR statistic ????Avg. log likelihood Prob(LR statistic)Obs with Dep=0 7 ?????Total obs 16Obs with Dep=19于是,我们可得到Logit 模型为:V Q i0177.0004.0107.11Y ˆ++-= () () ()685.40R 2MCF = , LR(2)=如果在Binary estination 这一栏中选择Probit 估计方法,可得到如下表:Dependent Variable: YMethod: ML - Binary Probit (Quadratic hill climbing) Date: 05/22/11 Time: 22:25 Sample: 1 16Included observations: 16Convergence achieved after 5 iterationsCovariance matrix computed using second derivativesVariableCoefficientStd. Error z-StatisticProb.??C Q VMcFadden R-squared ????Mean dependent var . dependent var ????. of regression Akaike info criterion ????Sum squared resid Schwarz criterion ????Log likelihood Hannan-Quinn criter. ????Restr. log likelihood LR statistic ????Avg. log likelihood Prob(LR statistic)Obs with Dep=0 7 ?????Total obs 16Obs with Dep=19于是,我们可得到Probit 模型为:V Q i0105.00024.035.66Y ˆ++-= () () ()763.40R 2MCF = , LR(2)=第7章练习6 下表列出了美国、加拿大、英国在1980~1999年的失业率Y 以及对制造业的补偿X 的相关数据资料。

解:(1)根据Eview 软件操作得如下表: 美国(US ):Dependent Variable: Y Method: Least Squares Date: 05/22/11 Time: 22:38 Sample: 1980 1999Included observations: 20VariableCoefficientStd. Error t-StatisticProb.??C XR-squared ????Mean dependent var Adjusted R-squared ????. dependent var . of regression ????Akaike info criterion Sum squared resid ????Schwarz criterion Log likelihood ????Hannan-Quinn criter. F-statistic ????Durbin-Watson stat Prob(F-statistic)根据上表可得对美国的OLS 估计结果为:tt X 0454.05686.10Y ˆ-= () () 4215.02=R , 3893.02=R , .=, RSS=加拿大(CA):Dependent Variable: Y Method: Least Squares Date: 05/22/11 Time: 22:43 Sample: 1980 1999Included observations: 20VariableCoefficientStd. Error t-StatisticProb.??C XR-squared????Mean dependent var Adjusted R-squared ????. dependent var . of regression ????Akaike info criterion Sum squared resid ????Schwarz criterion Log likelihood ????Hannan-Quinn criter. F-statistic ????Durbin-Watson stat Prob(F-statistic)同样,根据上表可得对加拿大(CA )的OLS 估计结果为:tt X 0066.0425.39Y ˆ-= () ()0048.02=R , 05.02-=R , .=, RSS=英国(UK ):Dependent Variable: Y Method: Least Squares Date: 05/22/11 Time: 22:48 Sample: 1980 1999Included observations: 20VariableCoefficientStd. Error t-StatisticProb.??C XR-squared????Mean dependent var Adjusted R-squared ????. dependent var . of regression ????Akaike info criterion Sum squared resid ????Schwarz criterion Log likelihood ????Hannan-Quinn criter. F-statistic ????Durbin-Watson stat Prob(F-statistic)同样,根据上表可得对英国(UK )的OLS 估计结果为:tt X 0466.0543.512Y ˆ-= () ()3036.02=R , 29.932=R , .=, RSS=(2)将三个国家的数据合并成一个样本(共60个样本点),根据Eview 软件得:OLS 估计结果如下:Dependent Variable: Y Method: Least Squares Date: 05/22/11 Time: 22:58 Sample: 1980 2039Included observations: 60VariableCoefficientStd. Error t-StatisticProb.??C XR-squared ????Mean dependent var Adjusted R-squared ????. dependent var . of regression ????Akaike info criterion Sum squared resid ????Schwarz criterion Log likelihood ????Hannan-Quinn criter. F-statistic ????Durbin-Watson stat Prob(F-statistic)根据上表得估计方程为:tt X 0495.049.112Y ˆ-= () ()3036.02=R , 2916.02=R , .=, RSS=(3)在Eviews 软件下,估计变截距固定影响模型得到如下结果:固定影响模型可按最小二乘虚拟变量(LSDV )模型估计,记D 2为加拿大(CA )的虚拟变量;即观测值属于CA 时取值为1,其他取值为0;记D 3为英国的虚拟变量,取值规律同D 2,所以,LSDV 模型的OLS 估计结果如下:X D D it 0383.0011.29221.19348.9Y 32-++=() () () ()5048.02=R , 4783.02=R , .=, RSS=美国(US )没有设定虚拟变量,成为比较的基准。

可以看出,该结果与上述固定效应模型的估计结果是一致的。

(4)为了比较以上三个模型,需要进行如下两个F 检验。

首先,进行“截距和斜率在不同的横截面样本点和时间上都相同”的假设检验,相应的F 检验为: ()()()[]()()()[]1,11/11/S -S F 1132+-+-+-=k n nT k n S k n ~F[(n-1)(k+1),nT-n(k+1)]其中,S 3为第二类模型,即合成的大样本模型相应的残差平方和,S 1为第一类模型,即按横截面样本点分别估计的各单一方程的残差平方和。

如果接受该假设,则选取第二类模型。

如果该假设被拒绝,则再进行“斜率在不同的横截面样本点和时间上都相同,但截距不相同”的假设,相应的F 检验为:()()[]()[]1/1/S -S F 1122+--=k n nT S k n ~F[(n-1)k,nT-n(k+1)] 其中,S 2为第三类模型,即固定效应模型的相应的残差平方和。

如果接受该假设,则选取第三类模型。

拒绝该假设,则选取第一类模型,即按横截面样本点分别估计的各单一的模型方程。

由上述估计结果,知:7.11114.1406.4487.522S 1=++= 4.9117S 2= 5.8165S 3=于是, 2F =, 1F =对于2F ,在5%的显着性水平下,自由度为(4,54)的F 分布的临界值为()4.5254,4F 0.05=,可见拒绝“截距和斜率在不同的横截面样本点和时间上都相同”的假设。

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