Unit root tests
A)use the standard normal distribution since they are based on the t-statistic.
B)cannot use the standard normal distribution for statistical inference. As a result the ADF statistic has its own special table of critical values.
C)can use the standard normal distribution only when testing that the level variable is stationary, but not the difference variable.
D)can use the standard normal distribution but only if HAC standard errors were computed.

Question

Quizplus · Accepted Answer

Unit root tests, such as the Augmented Dickey-Fuller test, cannot use the standard normal distribution for statistical inference. Instead, the ADF statistic has its own special table of critical values. This is because the test involves a time series regression with serially correlated errors, which violates the assumptions of the standard normal distribution.

Unit Root Tests