1. (15 marks) As a researcher you have been given data on N = 4,642 infant births and are asked to examine factors that determine the outcome of a low birthweight baby. Suppose you estimate two probit models (Model 1 and 2) with dependent variable LBWEIGHT = 1 if it is a low birthweight baby and 0 otherwise, MAGE is the mother's age, PRENATALI = 1 if first prenatal visit is in 1 trimester and 0 otherwise, and MBSMOKE = 1 if the mother smoked and 0 otherwise. The results are in Table below (Note that C refers to a constant and standard error are given in parantheses.) Table 1: Estimates from model 1 and 2 | MAGE | PRENATAL1 | MBSMOKE MAGE Model 1 -1.2581 -0.0103 -0.1568 0.3974 (se) (0.1436) | (0.0054) (0.071) (0.067) Model 2 -0.1209 -0.1012 -0.1387 0.4061 0.0017 (se) (0.4972) | (0.0385) (0.0716) | (0.0672) | (0.0007) a. In Model 1, comment on estimated signs and significance of the coefficients on PRENATALl and MBSMOKE (2 marks). b. Using Model 1, calculate the marginal effect on the probability of a low birthweight baby given an increase in the mother's age by 1 year, for a woman who is 20 years old with PRENATALI = 0 and MBSMOKE=0. Repeat this calculation for a woma who is 50 years old. Do the results make sense? (3 marks). c. Using Model 2, calculate the marginal effect on the probability of a low birthweight baby given an increase in the mother's age by 1 year, for a woman who is 20 years old with PRENATALI = 0 and MBSMOKE = 0. Repeat this calculation for a woman who is 50 years old. Compare these results to those in part (b). (3 marks). d. Using Model 2, calculate the impact of a prenatal visit in the first trimester on the probability of having a low birthweight baby for a woman who is 30 years old and smokes. (2 marks). e. Using Model 2, calculate the impact of a mother smoking on the probability having a low birth-weight baby given that she is 30 years old and had a prenatal visit in the first trimester. (2 marks). f. Using Model 2, calculate the age at which the probability of a low birthweight baby is a minimum