I'm having trouble with this textbook question and would be extremely grateful if someone solved and showed me the steps to the solution of this question.

1. A professor decides to run an experiment to measure the effect of time pressure on nal exam scores. He gives each of the 400 students in his course the same nal exam, but some students have 90 minutes to complete the exam, while others have 120 minutes- Each student is randomly assigned one of the examination times, based on the ip of a coin. Let K denote the number of points scored on the exam by the 2"\" student (0 g Y} s 100), let X; denote the amount of time that the student has to complete the exam (Xi = 60 or 120), and consider the regression model i"- = 130 + ,61X + up a. Explain what the term in represents. Why will different students have different values of in? b. Explain why E(u,>|X,>) = 0 for this regression model. o. Are the i.i.d. draw assumption satised? Explain. d. The estimated regression is f\