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我使用华宇功能R.如果我有一组数据,X1的怀疑,我想弄清楚这是最好的ARIMA模型:华宇结构中的R
> arima(diff(x1),order=c(1,0,1))
Series: diff(x1)
ARIMA(1,0,1) with non-zero mean
Coefficients:
ar1 ma1 intercept
0.3835 -1.0000 3e-03
s.e. 0.1082 0.0339 6e-04
sigma^2 estimated as 0.005576: log likelihood=88.75
AIC=-169.5 AICc=-168.95 BIC=-160.13
> arima(x1,order=c(1,1,1))
Series: x1
ARIMA(1,1,1)
Coefficients:
ar1 ma1
0.4238 -0.8984
s.e. 0.1202 0.0489
sigma^2 estimated as 0.006367: log likelihood=84.98
AIC=-163.96 AICc=-163.63 BIC=-156.93
为什么我获得不同的值