a. If you take a sample to get an estimate, and then take a different sample but from the same population and get a significantly different estimate, is this normal? b. What assumptions makes an OLS estimator BLUE (7 Marks) c. What is the relationship between level of significance and level of confidence (6 marks easy) d. Difference between null and alternative hypothesis (6 Marks) e. What is serial correlation and how does it affect an OLS estimate f. What do we mean when we say an OLS estimator is efficient g. What does critical value mean