对原始数据进行单整检验,服从一阶单整,又进行协整检验,存在三个协整向量,然后运用下面程序:
proc varmax data=a;
model p1-p4 / p=3 ecm=(rank=3 normalize=p1);
run;
主要结果:
Information Criteria
AICC -37.6794
HQC -37.4193
AIC -37.7006
SBC -37.0024
FPEC 4.24E-17
Schematic Representation of Cross Correlations of Residuals
Variable/
Lag 0 1 2 3 4 5 6 7 8 9 10 11 12
p1 ++++ .... .... +++. .... .... .... .... .... .... .... .... ....
p2 ++++ .... .... ++.. .... .... .... .... .... .... .... ---- ....
p3 ++++ .... .... +++. .... .... .... .... .... .... .... .... ..+.
p4 ++++ .... .... +++. .... .... .... .... .... .... .... .... ....
+ is > 2*std error, - is < -2*std error, . is between
Portmanteau Test for Cross
Correlations of Residuals
Up To
Lag DF Chi-Square Pr > ChiSq
4 16 28.75 0.0256
5 32 47.84 0.0356
6 48 58.50 0.1425
7 64 77.91 0.1135
8 80 91.09 0.1864
9 96 113.79 0.1039
10 112 133.83 0.0782
11 128 149.62 0.0929
12 144 167.17 0.0906
The VARMAX Procedure
Univariate Model White Noise Diagnostics
Durbin Normality ARCH
Variable Watson Chi-Square Pr > ChiSq F Value Pr > F
p1 1.95946 55.86 <.0001 5.99 0.0152
p2 1.97668 103.12 <.0001 5.66 0.0182
p3 1.98071 26.37 <.0001 10.98 0.0011
p4 1.99745 98.61 <.0001 19.54 <.0001
Univariate Model AR Diagnostics
AR1 AR2 AR3 AR4
Variable F Value Pr > F F Value Pr > F F Value Pr > F F Value Pr > F
p1 0.03 0.8591 0.02 0.9793 2.76 0.0428 2.43 0.0484
p2 0.20 0.6532 0.11 0.9003 2.55 0.0562 1.95 0.1025
p3 0.03 0.8691 0.12 0.8900 2.17 0.0926 1.64 0.1639
p4 0.03 0.8659 0.05 0.9541 0.94 0.4229 0.76 0.5536
几个问题:
1、误差项滞后阶数p如何确定?题目中用了p=3。但似乎不合适,,因为没通过白噪声检验。换了p=3,4,5,6,7.8,9等,还是不行?怎么处理啊?
2、Portmanteau Test是否是检验残差之间的相关性?这个结果说明什么呢?滞后4-5在5%水平相关?滞后10、11、12在10%水平相关?
这个结果怎么理解与运用啊?
谢谢达人,希望能够耐心看一下!再次感谢!