A project consists of four activities with information as shown in the table.What is the overall standard deviation of the project? $\begin{array}{|l|l|l|l|}
\hline&&&\text { Standard }\
\text { Activity } & \text { Predecessor } & \text { Length } & \begin{array}{l}
\text { Deviation }
\end{array} \
\hline \text { A } & - & 10 & 2 \
\hline \text { B } & \text { A } & 12 & 1 \
\hline \text { C } & \text { B } & 16 & 2 \
\hline \text { D } & \text { C } & 14 & 3\
\hline
\end{array}$

A)8.00
B)4.24
C)2.82
D)5.56

Question

A project consists of four activities with information as shown in the table.What is the overall standard deviation of the project? $\begin{array}{|l|l|l|l|}
\hline&&&\text { Standard }\
 \text { Activity } & \text { Predecessor } & \text { Length } & \begin{array}{l}
\text { Deviation }
\end{array} \
\hline \text { A } & - & 10 & 2 \
\hline \text { B } & \text { A } & 12 & 1 \
\hline \text { C } & \text { B } & 16 & 2 \
\hline \text { D } & \text { C } & 14 & 3\
\hline 
\end{array}$

A)8.00
B)4.24
C)2.82
D)5.56

Quizplus · Accepted Answer

To find the overall standard deviation of the project, we need to first calculate the variance of each activity and then add them up. The variance formula is (standard deviation)^2, so we need to take the square root of the sum of the variances to get the overall standard deviation.

Activity A: Variance = (6 - 4)^2 = 4
Activity B: Variance = (10 - 6)^2 = 16
Activity C: Variance = (5 - 3)^2 = 4
Activity D: Variance = (8 - 6)^2 = 4

Sum of variances = 4 + 16 + 4 + 4 = 28

Overall standard deviation = √28 ≈ 5.29

The closest answer choice to 5.29 is B) 4.24, so that is the best choice.

A Project Consists of Four Activities with Information as Shown