1 . The two stage least squares (2SLS) estimator has a lower variance than the OLS estimator? (True or False)

2. The instrumental variables method cannot be used if the number of endogenous variables is smaller than the number of instrumental variables. (True or False)

3. Even if the instrumental variable (IV) does not satisfy all the assumptions for a valid IV, it is less biased than OLS when there is an omitted variable. (True or False)

Provide proper explanation