问题如下图：
选项：
A. 
B. 
C. 
解释：
请问此处market premium的用处和含义是
NO.PZ2015121802000041 问题如下 A stowith beta of 1.5 is selling for $20 anp$1 vinyeen if the prishoul$21 yeen The stois unrvalueor overvalue Assuming the risk-free rate is 5%, expectemarket premium is 5%. A.The stois unrvalue investor shoulbuy it. B.The sotis overvalue investor shoulshort it. C.The sotis unrvalue investor shoulshort it. B is correct.Expectereturn on CAPM = 5 + 1.5 * 5= 12.5%Estimatereturn on sto= (21 - 20 + 1) / 20 = 10%The estimatereturn is less thexpectereturn on CAPM, incating ththe stois overvalue investor shoulshort it. 麻烦具体讲一下这中间的分析过程
NO.PZ2015121802000041 问题如下 A stowith beta of 1.5 is selling for $20 anp$1 vinyeen if the prishoul$21 yeen The stois unrvalueor overvalue Assuming the risk-free rate is 5%, expectemarket premium is 5%. A.The stois unrprice investor shoulbuy it. B.The sotis overvalue investor shoulshort it. C.The sotis unrvalue investor shoulshort it. B is correct.Expectereturn on CAPM = 5 + 1.5 * 5= 12.5%Estimatereturn on sto= (21 - 20 + 1) / 20 = 10%The estimatereturn is less thexpectereturn on CAPM, incating ththe stois overvalue investor shoulshort it. CAPM公式E(r)=Rf+beta*(Rm-Rf)，本题第一个计算为啥是beta1.5乘以5呢，Rm-Rf不是为0么
NO.PZ2015121802000041 问题如下 A stowith beta of 1.5 is selling for $20 anp$1 vinyeen if the prishoul$21 yeen The stois unrvalueor overvalue Assuming the risk-free rate is 5%, expectemarket premium is 5%. A.The stois unrprice investor shoulbuy it. B.The sotis overvalue investor shoulshort it. C.The sotis unrvalue investor shoulshort it. B is correct.Expectereturn on CAPM = 5 + 1.5 * 5= 12.5%Estimatereturn on sto= (21 - 20 + 1) / 20 = 10%The estimatereturn is less thexpectereturn on CAPM, incating ththe stois overvalue investor shoulshort it. 想问下题目第一句里说的 “A stowith beta of 1.5 is selling for $20”，指的是0时刻的价格是20对吗？
NO.PZ2015121802000041 问题如下 A stowith beta of 1.5 is selling for $20 anp$1 vinyeen if the prishoul$21 yeen The stois unrvalueor overvalue Assuming the risk-free rate is 5%, expectemarket premium is 5%. A.The stois unrprice investor shoulbuy it. B.The sotis overvalue investor shoulshort it. C.The sotis unrvalue investor shoulshort it. B is correct.Expectereturn on CAPM = 5 + 1.5 * 5= 12.5%Estimatereturn on sto= (21 - 20 + 1) / 20 = 10%The estimatereturn is less thexpectereturn on CAPM, incating ththe stois overvalue investor shoulshort it. 我之前理解capm模型计算出来的结果是一个预期收益，比如这个数是20%，那代表这支股票预期有20%的收益；但实际上这支股票只上涨了10%， 那么我会认为，该股还有10%的上涨空间，所以应该继续持有（换句话说就是该股股价被低估了）。当然从答案我知道这种理解是错的，那么capm正确的理解和用法是什么呢？
NO.PZ2015121802000041 请问为什么capm收益大于实际收益就是被高估？
