This paper- [Miller, P., Mulvey, C., & Martin, N. (2005). Birth weight and schooling and earnings: estimates from a sample of twins. Economics Letters, 86(3), 387-392.)] highlights several issues that are raised as limitations of using twins data to estimate returns to education. i. Write the general Mincerian returns to education function. (2 marks) ii. What is the econometric problem in the estimation of the Mincerian returns to education function that is addressed by the use of twins data? - Be sure to explain the problem and the assumptions that are made with the use of twins data in order to deal with the econometric problem. (6 marks) iii. However, such studies are not without criticisms, the paper above by Miller et al. highlights some of the criticisms. Mention two of those criticisms discussed in the paper. (4 marks) iv. Which country does the data used in the paper come from