NO.PZ2019040801000072
问题如下:
Analyst Amy gathers the follwing data for the return on the market and the return on Crude Oil. Please calculate the covariance of returns between Crude Oil and the market.
Probability Matrix
选项:
A.
0.66%
B.
1.05%
C.
0.28%
D.
2.68
解释:
A is correct.
考点:Covariance
解析: Cov(A,B) = E(AB) - E(A)*E(B)
E(AB) = 30%*25%*0.3+15%*20%*0.4 +10%*0*0.3 = 3.45%
E(A) = 30%*30%+15%*40%+10%*30%= 18%
E(B) = 25%*30%+20%*40%+0*30%=15.5%
所以Cov(A,B) = E(AB) - E(A)*E(B)=0.66%
E(AB) = 30%*25%*0.3+15%*20%*0.4 +10%*0*0.3 = 3.45%
第三项R_oil =10%, R_mkt=0%,概率是0.03,为什么乘出来不是0,而是10%*0*0.3?