Answer:
Given that,
Expected return on Z and Y,
Rz = 0.15 and Ry =0.35
Standard deviations:
Sz = 0.2, Sy = 0.4
correlation coefficient: rxy = 0.25
Expected return on portfolio = Rz × wz + Ry × wy
where, wz and wy are weights of Z and Y respectively in portfolio.
Standard deviation of portfolio:
[tex]\sqrt{(wz\times Sz)^{2}+(wy\times Sy)^{2}+2\times rxy\times wz\times wy\times Sz\times Sy }[/tex]
Table attached with this answer shows mean return and standard deviation at different combinations of weights: