4. (To answer this question, please thoroughly review the attached article - How Detroit Went Broke). In this question, we try the concept of formulating an empirical research project before finding the data. Assume you are serving as a consultant to the newly-elected Mayor of the City of Detroit. According to the article, the city lost more than half of its population in 50 years. Per Urban Economics theories, a city's economic fortune depends largely on its population growth. Therefore, you figure you first step is to identify the key factors that lead to such a dramatic population decline which will help you to formulate some economic advices to the Mayor. The Mayor's economic plan for the City depends on your findings. Since the above article is highly descriptive, as an individual with a background in data analytics, you would like to propose a more rigorous analysis. Formulating a regression model is on the top of your list. You also understand the validity of an empirical model depends critically on how well it is specified. (1) Specify the model you would try to estimate? Identify and justify the key variables that enter your model. What are the expected impacts of