A Company Has a PERT Project with Path B?d?e?g?i That

question 31

Essay

A company has a PERT project with path b?d?e?g?i that has these activity time estimates in days:
$$\begin{array} { c c c c } \text { Activity } & \begin{array} { c } \text { Optimistic } \\\text { t }_o\end{array} & \begin{array} { c } \text { Most Likely } \\\text { t }_m \\\end{array} & \begin{array} { c } \text { Pessimistic } \\\text { t }_p\end{array} \\\hline \text { b } & 15 & 17 & 20 \\ \text { d } & 21 & 22 & 22 \\ \text { e } & 27 & 30 & 35 \\ \text { g } & 23 & 27 & 29 \\\text {i}& 25 & 31 & 34 \\\end{array}$$
a. What is the expected duration for activity "e"?
b. What is the variance for activity "b"?
c. What is the standard deviation of the path?