Using the data in the following$$ table, and the fact that the correlation of A and B is $0\mathrm{.}67,$ calculate the volatility$($standard deviation$)$ of a portfolio that is $70\%$ invested in stock A and $30\%$ invested in stock B$.($Click on the following icon in order to copy its contents into a$$ spreadsheet.$)$

Realized Returns

Year

Stock A

Stock B

$2008$

negative $2\%$

$26\%$

$2009$

$17\%$

$40\%$

$2010$

$6\%$

$9\%$

$2011$

negative $4\%$

negative $4\%$

$2012$

$1\%$

negative $12\%$

$2013$

$15\%$

$23\%$

Question content area bottom

Part $1$

The standard deviation of the portfolio is

$$

enter your response here$\%.($Round to two decimal$$ places.$)$