$7-7.($Calculating expected rates of return and risk$)$ Syntex, Inc., is considering an in$-$ vestment in one of two common stocks. Given the information that follows, which investment is better, based on risk $($as measured by the standard deviation$)$ and return?

Common Stock A Common Stock B

Probability Return Probability Return

$\mathrm{.}3011\%\mathrm{.}2025\%$

$\mathrm{.}4015\%\mathrm{.}306\%$

$\mathrm{.}3019\%\mathrm{.}3014\%$

$\mathrm{.}2022\%$