1) Using the Work break structure provided below, calculate the expected task times, perform CPM, and compute the standard deviation of project time.

\begin{tabular}{|c|c|c|c|c|} \hline Task & Predecessor & Most likely & Optimistic & Pessimistic \\ \hline A & & 3 days & 2 & 4 \\ \hline B & A & 10 days & 8 & 18 \\ \hline C & A & 5 days & 3 & 10 \\ \hline D & B & 3 days & 3 & 6 \\ \hline E & B,C & 15 days & 13 & 17 \\ \hline F & D & 8 days & 4 & 10 \\ \hline \end{tabular}