You decide to invest in a portfolio consisting of $19$ percent Stock $x,49$ percent Stock $Y,$ and the remainder in Stock $Z.$ Based on the following information, what is the standard deviation of your portfolio? Please show all your work, including intermediary steps.

$\backslash$table$[[,,\backslash$table$[[$Return if State Occurs of$],[$Economy$]]],[$State of Economy,$\backslash$table$[[$Probability of$],[$State of$],[$Economy$]],$Stock A$,$Stock B$,$Stock C$],[$Normal$,\mathrm{.}80,10\mathrm{.}30\%,3\mathrm{.}70\%,12\mathrm{.}70\%$