There is another research on the relationship between average daily earnings and age. $! = 15 + 2.4 R2 = 0.02, SER =3.5 (8.85) (1.02) 4. Interpret the result carefully. (should include constant, slope coefficient, R2 .) 5. Conduct a hypothesis testing on the slope coefficient ( H0: slope=0). 6. How much more you would make daily at the age of 50 compare to that of age 20? Do you think the result is plausible? 7. It turned out that the old residual of the regression model has non-zero correlation-coefficient with the existing regressor of age and there is a bias in the slope. List at least 2 potential variables(factors) that could satisfy the conditions of omitted variable. (Explain why you think the choice of your new factors could meet the 2 conditions.)