(1)必要报酬率=5%+1.5×(13%-5%)=17%
(2)必要报酬率=5%+0.8×(13%-5%)=11.4%
大于期望报酬率11%,所以应当进行投资
(3)12.2%=5%+β×(13%-5%)
推出β值=0.9