NO.PZ2023040502000045
问题如下:
Luke examines West Texas Intermediate (WTI) monthly crude
oil price data, expressed in US dollars per barrel, for the 181-month period from
August 2000 through August 2015.
Based on the data for the AR(1) model( the critical value is 1.97), he can conclude that the:
选项:
A.residuals are not serially correlated.
autocorrelations do not differ significantly from zero.
standard error for each of the autocorrelations is
0.0745.
解释:
The standard error of the autocorrelations is
calculated as , where T
represents the number of observations used in the regression. Therefore, the
standard error for each of the autocorrelations is
Choices A and B are
incorrect because two of the four autocorrelations have at-statistic in
absolute value that is greater than the critical value of the t-statistic of
1.97.
请问题目中的Lag3以及Lag4,t-statistic是小于1.96的,也就是不能拒绝Ho
在不能拒绝Ho的情况下,是不是表示就存在autocorrelation的现象呢?
我记得课上说只要Lag1-4中有任何一个接受H0,就需要修正了
那么B选项中所述“autocorrelations do not differ significantly from zero.”错在哪里呢?