> m1=arima(w1,order=c(8,1,6))> m1
Call:
arima(x = w1, order = c(8, 1, 6))
Coefficients:
ar1 ar2 ar3 ar4 ar5 ar6 ar7 ar8
0.4231 0.2276 -0.3326 -0.5617 0.5105 -0.2459 0.0637 -0.1422
s.e. 0.5027 0.2672 0.1978 0.1669 0.2728 0.3018 0.1353 0.0937
ma1 ma2 ma3 ma4 ma5 ma6
-0.4184 -0.4715 0.4936 0.5838 -0.8193 0.0657
s.e. 0.5088 0.2685 0.3096 0.2294 0.3119 0.4441
sigma^2 estimated as 0.0001175: log likelihood = 889, aic = -1748.01
> nihe<-ts(fitted(m1),start=1)
Error in ts(fitted(m1), start = 1) : 'ts'对象至少必需有一个或多个观察量
> fitted(m1)
NULL
请问是什么原因呀?