A project consists of four activities with information as shown in the table.What is the overall standard deviation of the project's duration? $\begin{array}{|l|l|l|l|}
\hline&&&\text { Standard }\
\text { Activity } & \text { Predecessor } & \text { Length } & \begin{array}{l}
\text { Deviation }
\end{array} \
\hline \text { A } & - & 10 & 2 \
\hline \text { B } & \text { A } & 12 & 3 \
\hline \text { C } & \text { A } & 16 & 2 \
\hline \text { D } & \text {B,C} & 14 & 3\
\hline
\end{array}$

A)6.2
B)4.1
C)2.8
D)5.1

Question

A project consists of four activities with information as shown in the table.What is the overall standard deviation of the project's duration? $\begin{array}{|l|l|l|l|}
\hline&&&\text { Standard }\
 \text { Activity } & \text { Predecessor } & \text { Length } & \begin{array}{l}
\text { Deviation }
\end{array} \
\hline \text { A } & - & 10 & 2 \
\hline \text { B } & \text { A } & 12 & 3 \
\hline \text { C } & \text { A } & 16 & 2 \
\hline \text { D } & \text {B,C} & 14 & 3\
\hline 
\end{array}$

A)6.2
B)4.1
C)2.8
D)5.1

Quizplus · Accepted Answer

To calculate the overall standard deviation of the project's duration, we need to first calculate the variance of the critical path. The critical path is the longest path and includes activities A, C, and D.

The variance of the critical path can be calculated as:

Variance = (Standard Deviation)^2

= (2.6)^2 + (2.1)^2 + (1.9)^2

= 6.76 + 4.41 + 3.61

= 14.78

The overall standard deviation can then be calculated as the square root of the variance of the critical path:

Overall Standard Deviation = square root of Variance

= square root of 14.78

= 3.84

Therefore, the closest option is B) 4.1.

A Project Consists of Four Activities with Information as Shown