非平稳时间序列分析汇编.docx
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非平稳时间序列分析汇编
非平稳时间序列分析
1、首先画出时序图如下:
从时序图中看出有明显的递增趋势,而该序列是一直递增,不随季节波动,所以认为该序列不存在季节特征。
故对原序列做一阶差分,画出一阶差分后的时序图如下:
从中可以看到一阶差分后序列仍然带有明显的增长趋势,再做二阶差分:
做完二阶差分可以看到,数据的趋势已经消除,接下来对二阶差分后的序列进行检验:
Autocorrelations
LagCovarianceCorrelation-198765432101234567891StdError
0577.3331.00000||********************|0
1-209.345-.36261|*******|.|0.071247
2-52.915660-.09166|.**|.|0.080069
39.1391950.01583|.|.|0.080600
415.3758920.02663|.|*.|0.080615
5-59.441547-.10296|.**|.|0.080660
6-23.834489-.04128|.*|.|0.081324
7100.2850.17370|.|***|0.081431
8-146.329-.25346|*****|.|0.083290
952.2286580.09047|.|**.|0.087118
1021.0085750.03639|.|*.|0.087593
11134.0180.23213|.|*****|0.087670
12-181.531-.31443|******|.|0.090736
1323.2684700.04030|.|*.|0.096108
1471.1121950.12317|.|**.|0.096194
15-105.621-.18295|****|.|0.096991
1637.5919960.06511|.|*.|0.098727
1723.0315060.03989|.|*.|0.098945
1845.6547450.07908|.|**.|0.099027
19-101.320-.17550|****|.|0.099347
20127.6070.22103|.|****|0.100908
21-61.519663-.10656|.**|.|0.103337
2235.8253170.06205|.|*.|0.103893
23-93.627333-.16217|.***|.|0.104081
2455.4512080.09605|.|**.|
从其自相关图中可以看出二阶差分后的序列自相关系数很快衰减为零,且都在两倍标准差范围之内,所以认为平稳,白噪声检验结果:
AutocorrelationCheckforWhiteNoise
ToChi-Pr>
LagSquareDFChiSq--------------------Autocorrelations--------------------
630.706<.0001-0.363-0.0920.0160.027-0.103-0.041
1284.5412<.00010.174-0.2530.0900.0360.232-0.314
1897.9818<.00010.0400.123-0.1830.0650.0400.079
24126.9924<.0001-0.1750.221-0.1070.062-0.1620.096
P值都小于0.05,认为不是白噪声。
接下来对模型进行定阶:
MinimumInformationCriterion
LagsMA0MA1MA2MA3MA4MA5
AR06.3569056.1418316.1498386.1755526.1915646.203649
AR16.2369226.1681216.151526.1726746.1869626.193905
AR26.1932156.1808186.1773376.1974076.2032246.207239
AR36.197486.2030816.2028376.2210836.2153136.188712
AR46.2203136.229496.2274456.2418836.1628376.189358
AR56.2221316.2367396.2440256.2649686.1859636.210425
Errorseriesmodel:
AR(10)
MinimumTableValue:
BIC(0,1)=6.141831
从sas的定阶结果来看,BIC(0,1)取得最小值,所以选取MA
(1)模型,接下来对模型进行拟合:
得到模型为:
模型检验结果为:
ConditionalLeastSquaresEstimation
StandardApprox
ParameterEstimateErrortValuePr>|t|Lag
MU0.402860.169002.380.01810
MA1,10.890630.0326627.27<.00011
检验结果显示都显著。
接下来利用此模型对1997年的四个季度进行预测:
Forecastsforvariablex
时间ForecastStdError95%ConfidenceLimits
1997一季度7759.206131.22767698.00117820.4112
1997二季度7842.613540.30487763.61757921.6095
1997三季度7926.423748.94447830.49458022.3530
1997四季度8010.636857.43567898.06518123.2085
预测图:
本题代码
dataaa;
inputx@@;
difx=dif(x);
dif2x=dif(difx);
t=intnx('quarter','1jan1947'd,_n_-1);
formattyear4.;
cards;
227.8231.7236.1246.3252.6259.9266.8268.1263.0
259.5261.2258.9269.6279.3296.9308.4323.2331.1
337.9342.3345.3345.9351.7364.2371.0374.5373.7
368.7368.4368.7373.4381.9394.8403.1411.4417.8
420.5426.0430.8439.2448.1450.1457.2451.7444.4
448.6461.8475.0499.0512.0512.5516.9530.3529.2
532.2527.3531.8542.4553.2566.3579.0586.9594.1
597.7606.8615.3628.2637.5654.5663.4674.3679.9
701.2713.9730.4752.6775.6785.2798.6812.5822.2
828.2844.7861.2886.5910.8926.0943.6966.3979.9
999.31008.01020.31035.71053.81058.41104.21124.91144.4
1158.81198.51231.81256.71297.01347.91379.41404.41449.7
1463.91496.81526.41563.21571.31608.31670.61725.31783.5
1814.01847.91899.01954.52026.42088.72120.42166.82293.7
2356.22437.02491.42552.92629.72687.52761.72756.12818.8
2941.53076.63105.43197.73222.83221.03270.33287.83323.8
3388.23501.03596.83700.33824.43911.33975.64022.74100.4
4158.74238.84306.24376.64399.44455.84508.54573.14655.5
4731.44845.24914.55013.75105.35217.15329.25423.95501.3
5557.05681.45767.85796.85813.65849.05904.55959.46016.6
6138.36212.26281.16390.56458.46512.36584.86684.56773.6
6876.36977.67062.27140.57202.47293.47344.37426.67537.5
7593.6
;
procgplot;
plotx*tdifx*tdif2x*t;
symbolc=blacki=joinv=star;
run;
procarima;
identifyvar=x(1,1)nlag=8minicp=(0:
5)q=(0:
5);
estimateq=1;
forecastlead=5id=tinterval=quarterout=results;
run;
procgplotdata=results;
plotx*t=1forecast*t=2l95*t=3u95*t=3/overlay;
symbol1c=blacki=nonev=star;
symbol2c=redi=joinv=none;
symbolc=greeni=joinv=nonel=32;
run;
2、首先画出时序图:
从时序图中可以看出序列存在递增趋势,而且存在季节性特征,接下来对序列进行一阶差分,画出差分后的时序图:
可以看到趋势已经消除,但季节性仍存在,对其进行检验:
Autocorrelations
LagCovarianceCorrelation-198765432101234567891StdError
016681.7471.00000||********************|0
1-3098.631-.18575|****|.|0.049568