NO.PZ2018101001000065
问题如下:
If given the time series is ARCH(1) and the model is εt2=a0+a1εt-12+ut, which of the followings is most likely correct?
选项:
A.a1 is not significantly different from 0.
B.a1 is significantly different from 0.
C.the variance of the error terms for this time series cannot be predicted.
解释:
B is correct.
考点: ARCH & summary of AR assumption.
解析:若一个时间序列的ARCH(1)成立,则模型中的a1不等于0,并且这组时间序列的方差是可以被预测的。所以只有B选项正确。
a1≠0,不就是有异方差,所以ARCH(1)不成立?