Time Estimates for Individual Activities

Question

Time Estimates for Individual Activities:

A) Weighted Average Activity Time, t =  (a + 4m + b)/6

B) Standard deviation of activity times, σ_t = (b-a)/6

C) Standard deviation of project completion, σ_T= √ (∑ σ_t²)

a = optimistic completion time (1 in 100 chance of completing the activity earlier under normal conditions)
m = most likely activity time
b = pessimistic completion time (1 in 100 chance of completing the activity later under normal conditions)
t = weighted average activity time
σ_t = standard deviation of activity completion
σ_T = standard deviation of project completion