问一道题：NO.PZ2017092702000053

问题如下：

The mean monthly return and the standard deviation for three industry sectors are shown in the following table.

Based on the coefficient of variation, the riskiest sector is:

选项：

utilities.

materials.

industrials.

解释：

B is correct.

The coefficient of variation (CV) is the ratio of the standard deviation to the mean, where a higher CV implies greater risk per unit of return.

${l}CV_{UTIL}=\frac s{\overline X}=\frac{1.23\%}{2.10\%}=0.59\\CV_{MATR}=\frac s{\overline X}=\frac{1.35\%}{1.25\%}=1.08\\CV_{MATR}=\frac s{\overline X}=\frac{1.52\%}{3.01\%}=0.51$