2. Portfolio sorting is one of the most popular way to identify predictability in the cross section of stock returns.

a). Briefly discuss the difference between sequential and independent double (Bi-variate) sorting. What would happen if the two sorting variables are independent with each other?

b). Comparing with the portfolio sorting approach, what are the advantages and disadvantages of the Fama-Macbeth regression approach

Ref: http://www.business.unr.edu/faculty/liuc/files/BADM742/Fama_MacBeth_1973_1.pdf