问题如下：
Which of the following statements about positive serial correlation is most likely correct?
选项：
A.It will not affect the consistency and estimation of regression coefficients.
B.It will lead a higher standard errors of regression coefficients.
C.It will lead a smaller t-statistics of regression coefficients.
解释：
A is correct.
考点: Serial correlation.
解析: 本题考的是正序列相关的特征。正序列相关只会影响残值ε的波动，但对回归方程本身的精确度无影响，也不会影响系数的估计。但正序列相关会使标准误变小，造成t统计量变大。所以A的描述是正确的，B和C的描述是错误的。选择A。
负的序列自相关会导致t值和standard error变大还是小呢？ 那异方差和条件异方差会导致t值和standard error变大还是小呢？
