A project consists of four consecutive tasks that have average duration and worst-case duration estimates (in days)as shown in the table.Use Newbold's model to determine the aggregated buffer of one standard deviation for this project. $$\begin{array} { | l | l | l | }
\hline \text { Activity } & \text { Average } & \text { Worst-Case } \
\hline \mathrm { X } & 12 & 20 \
\hline \mathrm { Y} & 20 & 25 \
\hline \mathrm { Z} & 14 & 24 \
\hline \mathrm { W } & 18 & 26 \
\hline
\end{array}$$
A)31 days
B)16 days
C)8 days
D)5 days

Question

A project consists of four consecutive tasks that have average duration and worst-case duration estimates (in days)as shown in the table.Use Newbold's model to determine the aggregated buffer of one standard deviation for this project. $$\begin{array} { | l | l | l | } 
\hline \text { Activity } & \text { Average } & \text { Worst-Case } \
\hline  \mathrm {  X } & 12 & 20 \
\hline  \mathrm { Y} & 20 & 25 \
\hline \mathrm {  Z} & 14 & 24 \
\hline \mathrm { W } & 18 & 26 \
\hline
\end{array}$$
A)31 days
B)16 days
C)8 days
D)5 days

Quizplus · Accepted Answer

Newbold's model calculates the aggregated buffer as one standard deviation of the project duration, using the formula: $$ \text{Buffer} = \sqrt{\sum (\frac{\text{Worst-Case} - \text{Average}}{6})^2} $$ For each task: $$ \text{X} = \frac{20-12}{6}, \text{Y} = \frac{25-20}{6}, \text{Z} = \frac{24-14}{6}, \text{W} = \frac{26-18}{6} $$ Summing the squares of these values and taking the square root gives the aggregated buffer of approximately 8 days.

A Project Consists of Four Consecutive Tasks That Have Average