Consider the following returns and states of the economy for TZ$.$Com.:

Economy

Probability

Return

Weak

$40\%$

$4\%$

Normal

$50\%$

$7\%$

Strong

$10\%$

$47\%$

What is the standard deviation of TZ$\text{'}$s returns? SET YOUR CALCULATOR TO FOUR DECIMAL PLACES AND ROUND TO $2$ DECIMAL PLACES AT THE END. DO NOT ENTER THE $\%.$ FOR EXAMPLE, IF YOUR ANSWER IS $7\mathrm{.}7011\%$ ENTER IT AS $7\mathrm{.}70.$