问一道题：NO.PZ2018070201000037 [ CFA I ]

NO.PZ2018070201000037 问题如下 What's the annugeometric mereturn of below investment over three years? A.-1.15%. B.2.5%. C.3.8%. A is correct.The annugeometric mereturn is   [(1  +  0.2)(1−0.3)(1  +  0.15)]1/3  −1  =  0.9661/3  −1  =  −0.0115  =  −1.15%\;{\lbrack(1\;+\;0.2)(1-0.3)(1\;+\;0.15)\rbrack}^{1/3}\;-1\;=\;0.966^{1/3}\;-1\;=\;-0.0115\;=\;-1.15\%[(1+0.2)(1−0.3)(1+0.15)]1/3−1=0.9661/3−1=−0.0115=−1.15% Three equity funmanagers have performanrecor summarizein the following table: Given a risk-free rate of return of 2.60%, whimanager performebest baseon the Sharpe ratio?Manager 1. Manager 2 Manager 3Manager 1Sharpe ratio= (Rp-Rf)/σp=（14.38%-2.6%）/10.53cor，请问cor是怎么算的？

NO.PZ2018070201000037 之前有个类似的题没开3次方，问题问的是over three years。当时那个的题解答是如果算年化的需要开三次，over the three的话直接乘完-1

老师 为什么这道题不用根号3