a) Consider a dataset of 2000 people, 1000 chosen randomly in 2010 and another 1000 chosen randomly in 2011. In both years, the same questions were asked. What kind of dataset is this?

b) A test preparation company advertises that the average student can raise their scores in ECON 101 by spending $120 on their course. One of your fellow students in ECON 399 takes a random sample of past ECON 101 students and finds using an OLS regression that those who have taken the course score 15 points lower on the final exam on average compared to those that did not take the course. Does this mean the test preparation course for ECON 101 is ineffective? Explain.

c) Consider the simple linear regression model. What is the expression for 𝛽o?

d) In words, what is Assumption SLR 2?