You are reading a research report where the authors run a regression for unemployment. They run the following regression: ??????????? = 0 1????? 2??? ? 2???? ? 2???????? ? 2????? ? 2??????? ? ? Where Unemployed=currently unemployed Hours=hours currently working on job Earnings=weekly earnings from current job State=coded variable where 1=Alabama, ..., 50=Wyoming Midwest=Midwest region of the country (20 pts) What are some common model specification problems associated with this model