A project has 3 independent stages that must be completed in sequence. The time to complete each stage is a random variable. The standard deviations of the completion times for the stages are σ₁ = 5, σ₂ = 4, σ₃ = 6. The standard deviation of the overall project completion time is: A)8.77 B)15.0 C)14.2 D)9.24

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Quizplus · Accepted Answer

The standard deviation of the overall project completion time is calculated by taking the square root of the sum of the squares of the individual standard deviations because the stages are independent. Thus, $\sqrt{5^2 + 4^2 + 6^2} = \sqrt{25 + 16 + 36} = \sqrt{77} \approx 8.77$.

A Project Has 3 Independent Stages That Must Be Completed