建一个ARIMAX模型,但模型的部分参数不显著,需要调优。就这个问题,想请教一个大牛们。
第一个模型为t_arimax_1
t_arimax_1
Call:
arimax(x = zoo.tra.e[1:620], order = c(1, 0, 6), seasonal = list(order = c(3,
1, 3), period = 7), xreg = newx.t[c(1:620), ])
Coefficients:
ar1 ma1 ma2 ma3 ma4 ma5 ma6
0.8401 -0.5136 -0.0083 -0.0756 0.0301 0.0043 -0.0848
s.e. 0.1699 0.1748 0.0717 0.0653 0.0511 0.0543 0.0516
sar1 sar2 sar3 sma1 sma2 sma3 rainfall
1.0589 -0.7213 0.0784 -1.9986 1.6731 -0.6743 0.0035
s.e. 0.3536 0.3042 0.0583 0.3558 0.4836 0.2849 0.0018
humidity t APRIL AUGUST DECEMBER FEBRUARY
0.0079 3e-04 -0.5908 -0.4042 0.1690 -1.2623
s.e. 0.0030 4e-04 0.2368 0.2278 0.2489 0.2356
JULY JUNE MARCH MAY OCTOBER SEPTEMBER
-0.3899 -0.4344 -0.6105 -0.7432 -0.3623 0.2925
s.e. 0.2303 0.2296 0.2295 0.2270 0.2309 0.2305
WEEKEND Holiday2
0.1092 -1.9799
s.e. 0.1098 0.0949
WEEKEND明显不显著,剔除WEEKEND,重新拟合模型
> t_arimax_1.1
Call:
arimax(x = zoo.tra.e[1:620], order = c(1, 0, 6), seasonal = list(order = c(3,
1, 3), period = 7), xreg = newx.t2[c(1:620), ])
Coefficients:
ar1 ma1 ma2 ma3 ma4 ma5 ma6
0.8366 -0.5068 -0.0074 -0.0788 0.0291 0.0094 -0.0813
s.e. 0.1599 0.1649 0.0695 0.0634 0.0506 0.0532 0.0505
sar1 sar2 sar3 sma1 sma2 sma3 rainfall
0.9877 -0.5186 0.0671 -1.9293 1.4120 -0.4822 0.0036
s.e. 0.5567 0.8050 0.0662 0.5603 1.2745 0.7696 0.0018
humidity t APRIL AUGUST DECEMBER FEBRUARY
0.0078 2e-04 -0.6123 -0.3977 0.1763 -1.2765
s.e. 0.0030 4e-04 0.2351 0.2330 0.2439 0.2375
JULY JUNE MARCH MAY OCTOBER SEPTEMBER
-0.3943 -0.4497 -0.6248 -0.7482 -0.3716 0.3029
s.e. 0.2317 0.2332 0.2330 0.2313 0.2307 0.2329
Holiday2
-1.9622
s.e. 0.0944
拟合效果比之前要好。但显然ma2的系数不显著,于是我采取疏系数模型,结果程序运行错误。
t_arimax_1.1<-arimax(zoo.tra.e[1:620],order=c(1,0,6),
seasonal=list(order=c(3,1,3),period=7),
fixed=c(NA,NA,0,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA),
xreg=newx.t2[c(1:620),])
Error in stats:::arima(x = x, order = order, seasonal = seasonal, xreg = xreg, :
wrong length for 'fixed'
两个问题向大家请教:
(一)fixed的长度如何确定,长度是不是1+6+3+3
(二)如何调优arimax模型,是不是一个一个的提出不显著参数?
谢谢!


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