Q: Answer yes or no to each of the items from ato c. If yes, briefly justify the statement, if no, provide acounter-example or disprove the statement.
a) We have a sample of an individuals, indexedby i = 1, · · · , n. For the i-th individual, we can observeXi andYi. If we assume our sample is i.i.d.cross-sectionally, it implies Xi and Yi are independent with eachother.
b) In multivariate OLS, we have threeregressors X1, X2, X3. If (X1, X2), (X1, X3), and (X3, X2) are notperfectly correlated, then we do not have the perfectmulticollinearity.
c) T-test is still valid when OLS assumption 1correct specification is violated.
