Suppose that the index model for stocks A and B is estimated from excess returns with the following results: R A = 3% + .7R M + e A R B = −2% + 1.2R M + e B σ M = 20%; R-square A = .20; R-square B =...

Suppose that the index model for stocks A and B is estimated from excess returns with the following results:
R_A = 3% + .7R_M + e_A

R_B = −2% + 1.2R_M + e_B

σ_M = 20%; R-square_A = .20;                    R-square_B = .12
What are the covariance and the correlation coefficient between the two stocks?