Q1. The following regression model tries to estimate educational performance (CGPA) of NSU Econ students. A researcher has proposed the following model: CGPA = B. + B.X + B.X + B.X + Here, X = Study Hours per week X = Financial condition (measured by Parent's income) X = Educational Background (measured by type of schooling in high school level i.e. is the student from English medium or Bangla medium background) It is a dummy variable, X = 0 if from English medium, X, =1 if from Bangla medium a) Hypothesize expected sign of the coefficients and provide explanation in support of your answer. b) What are the sources of "SPECIFICATION ERROR" in a regression model? Provide example for each type of specification error in context of this model. c) Provide example of one omitted variable in the context of this model and explain how the omitted variable you picked may introduce bias in estimates. d) Suppose the researcher wants to include students from Madrasa background also in the analysis. How would you do that? Write the new regression model