2. We have a linear model y = a + b * x + e, please answer the following questions. A. Please specify the four parts of the linear model mentioned above(4 points) y: x: (a,b): e: C. What is the OLS methodology to estimate (a, b)? (8 points) D. The OLS estimates are BLUE, what does each letter of "BLUE" mean? (8 points) E. How do you evaluate the significance of x? (10 points) F. How would you evaluate the fitness of the overall model ? (10 points)