Your question is Core Quant Concepts and Pitfalls. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Explain cointegration, what a view is in a Black-Litterman model, the problems with mean-variance optimization, issues when constructing a covariance matrix, and whether beta or R-squared is more important in factor regression.