Variance and Standard Deviation

State

$1$

$2$

$3$

$4$

Probability

$20\%$

$30\%$

$30\%$

$20\%$

Return on Stock A

$5\%$

$10\%$

$15\%$

$20\%$

Return on Stock B

$50\%$

$30\%$

$10\%$

$-10\%$

Calculate the expected return for Stock A

$11\%$

$20\%$

$12\mathrm{.}5\%$

$18\%$