1. Why is the OLS estimator so widely used? Is it superior to all other estimators?
2 What is meant by the mean-square error? Why and when is the rule to minimize the mean- square error useful? (b) Prove that the mean-square error equals the variance plus the square of the bias of the estimator.
3. What is meant by consistency? (b) Draw a figure of the sampling distribution of a consistent estimator.