I need the answer steps of the portfolio standard deviation, than you

Diversification Problem: \begin{tabular}{|c|c|c|c|} \hline Scenario & Probability & Stocks & Bonds \\ \hline Recession & 30% & 6% & 12% \\ \hline Normal & 50% & 13% & 7% \\ \hline Boom & 20% & 27% & 4% \\ \hline \end{tabular} Fill in the following table: Diversification Problem: \begin{tabular}{|c|c|c|c|} \hline Scenario & Probability & Stocks & Bonds \\ \hline Recession & 30% & 6% & 12% \\ \hline Normal & 50% & 13% & 7% \\ \hline Boom & 20% & 27% & 4% \\ \hline \end{tabular} Fill in the following table