问一道题：NO.PZ2015121801000045 [ CFA I ]

这道题是数量与组合两个学科的结合。首先要注意题干给的信息是geometric retur是求real rate of return for equities。

算术法求收益率，用加法，公式为：equity return=risk free rate + risk premium；

几何法求收益率，用乘法，公式为：(1+equity return)=(1+risk-free rate)(1+risk premium)

其中，1+risk-free rate= (1 + real risk-free interest rate) × (1 + expected inflation)

可以推导出

1+ real equity return= (1 + real risk-free interest rate) ×(1+risk premium)

1+ nominal equity return= (1 + real risk-free interest rate) × (1 + expected inflation) ×(1+risk premium)

1+ nominal equity return=(1+ real equity return) ×(1 + expected inflation)

根据表格的数据，有：

1+ nominal equity return=1 + 0.080

1 + real risk-free interest rate=1 + 0.0250

1 + expected inflation=1 + 0.0210

因此：

real equity return=(1 + 0.080)/(1 + 0.0210)-1 = 5.8%

risk premium for equities =(1 + 0.058)/(1 + 0.0250)-1 = 3.2%