大连海事大学计量经济学Eviews实验课讲义_5序列相关与异方差上机课
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第五课序列相关与异方差模型的处理
5.1序列相关模型
一、首先,结合案例数据(5_1_1)研究天津市城镇居民人均消费与人均可支配收入的关系,分析一阶线性相关存在时模型的检验与处理。
(1)案例数据:改革开放以来,天津市城镇居民人均消费性支出(CONSUM),人均可支配收入(INCOME)以及消费价格指数(PRICE)数据(1978—2000年)见下表。(数据来源:张晓峒,《计量经济学基础》,P152,例6.1)
(2)散点图
考虑到价格指数的影响,将CONSUM和INCOME各自除以价格指数,形成被解释变量和解释变量:CONSUM/PRICE和INCOME/PRICE,并作散点图如下,分析散点图,CONSUM/PRICE和INCOME/PRICE呈现线性相关。
(3)回归结果,Eviews输出结果报告,
得到回归方程CONSUM/PRICE = 111.4400081 + 0.7118287831*INCOME/PRICE
Dependent Variable: CONSUM/PRICE
Variable Coefficien
t Std. Error t-Statistic Prob.
C 111.4400 17.05592 6.533804 0.0000
INCOME/PRICE 0.711829 0.016899 42.12221 0.0000
Adjusted R-squared 0.987746 S.D. dependent var 296.7204
S.E. of regression 32.84676 Akaike info criterion 9.904525
Sum squared resid 22657.10 Schwarz criterion 10.00326
Log likelihood -111.9020 F-statistic 1774.281
Durbin-Watson stat 0.598571 Prob(F-statistic) 0.000000
05
.0
=
α水平上,T=23条件下,k=1时,临界值Dl=1.26,由结果可知,DW=0.59
LM统计量:
Breusch-Godfrey Serial Correlation LM Test:
Obs*R-squared 9.793792 Prob. Chi-Square(1) 0.001751
辅助回归:
Test Equation:
Dependent Variable: RESID Included observations: 23
Presample missing value lagged residuals set to zero.
Variable
Coefficien
t
Std. Error t-Statistic Prob. C 3.171015 13.26883 0.238982 0.8136 INCOME/PRICE -0.004662 0.013177 -0.353781 0.7272 RESID(-1)
0.678967
0.176298
3.851247
0.0010
R-squared
0.425817 Mean dependent var -1.40E-13 Adjusted R-squared 0.368399 S.D. dependent var 32.09156 S.E. of regression 25.50424 Akaike info criterion 9.436674 Sum squared resid 13009.32 Schwarz criterion 9.584782 Log likelihood -105.5217 F-statistic 7.416052 Durbin-Watson stat
2.005247 Prob(F-statistic)
0.003895
可见,卡方统计量TR 2=9.79,而05.0=α水平下,84.3)1(05.=χ,TR 2=9.79>84.3)1(05.=χ,因此,拒绝零假设,认为存在一阶序列相关。0.678967说明存在正相关。
(5)用广义最小二乘法估计参数
计算一阶相关系数7.02
6
.0121=-=-
=DW ρ,对原变量做广义差分,若令PRICE INCOME X PRICE CONSUM Y t t /,/==,令17.0--=t t t Y Y GDY , 17.0--=t t t X X GDX ,则以t GDY 和t GDX 为样本再次计算回归方程,GDY = 45.24890183 + 0.6782321994*GDX
Dependent Variable: GDY
Included observations: 22 after adjustments
Variable
t
Std. Error t-Statistic Prob.
GDX
0.678232
0.033983
19.95799 0.0000
R-squared
0.952190 Mean dependent var 269.1295 Adjusted R-squared 0.949799 S.D. dependent var 103.4908 S.E. of regression 23.18764 Akaike info criterion 9.211624 Sum squared resid 10753.33 Schwarz criterion 9.310809 Log likelihood -99.32786 F-statistic 398.3214 Durbin-Watson stat
2.308815 Prob(F-statistic)
0.000000
DW 值=2.3<4-du=4-1.43=2.57,已经消除序列相关。