A portfolio manager has made an investment that will generate returns that are subject to the state of the economy during the year. Use the following information to calculate the standard deviation of the return distribution for the portfolio.

Economic State Return Probability

E$($R$)$

Weak $15\%0\mathrm{.}30$ Var$($R$)$

Marginal $25\%0\mathrm{.}40$ Std$($R$)$

Strong $20\%0\mathrm{.}30$