Q1. Briefly describe the criterion used to obtain the ordinary least square estimator. [2] Q2. When estimating a regression in a sample why is a large sample observations preferred to mall sample? [2] Q3. Why is an efficient estimator a desirable property of the OLS estimator? [2] Q4. State the assumption(s) under the classical linear regression model geving rise to a biased standard error of the coefficient estimates when violated [2]