GLS involves A) writing the model in differences and ...

[tatyanajohnson]

GLS involves
 
  A) writing the model in differences and estimating it by OLS, using HAC standard errors.
  B) truncating the sample at both ends of the period, then estimating by OLS using HAC standard errors.
  C) checking the AIC rather than the BIC in choosing the maximum lag-length of the regressors.
  D) transforming the regression model so that the errors are homoskedastic and serially uncorrelated, and then estimating the transformed regression model by OLS.

Question 2

GLS is consistent and BLUE if
 
  A) X is predetermined.
  B) the error process is AR(1).
  C) X is strictly exogenous.
  D) all the roots are inside the unit circle.

[enass]

Answer to Question 1

Answer: D

Answer to Question 2

Answer: C