$($Expected rate of retumn and risk$)$ Summerville Inc. is considering an investment in one of two common stocks. Given the information in the popup window: $,$ which investment is better, based on the risk $($as measured by the standard deviation$)$ and return of each?

a$.$ The expected rate of return for Stock $A$ is

$\%.($Round to two decimal places$)$

Data table

$($Click on the following icon in order to copy its contents into a spreadsheet$)$

$\backslash$table$[[$COMMON STOCK A$,$COMMON STOCK B$],[$PROBABILITY$,$RETURN,PROBABILITY,RETURN$],[0\mathrm{.}20,12\%,0\mathrm{.}20,-6\%$