-What are tests of variable/model statistical significance? See regression tests! -What is - and what is the problem of - Multi-Colinearity? Define! Solve! -How would you solve for this? -What is Internal and External Validity? Explain! Q9: What is the difference between un-systematic and systematic risk? Show graph! - What type of risk can be diversified away? How would you do this? What statistical measures would you have to look at? Explain!.