$8-7.($Computing the expected rate of return and risk$)$ After a tumultuous period in the stock market, Logan Morgan is considering an investment in one of two portfolios. Given the information that follows, which investment is better, based on risk $($as measured by the standard deviation$)$ and return as measured by the expected rate of return?

Portfolio A Portfolio B

Probability Return Probability Return

$\mathrm{.}202\%\mathrm{.}105\%$

$\mathrm{.}5019\%\mathrm{.}307\%$

$\mathrm{.}3025\%\mathrm{.}4012\%$

$\mathrm{.}2014\%$

not in excel simple formula. thanks.