An activity has a pessimistic time that is four times as long as its most likely time and six times as long as its optimistic time.If the activity variance is 12,what is the expected time?
A)About 8 days
B)About 9 days
C)About 10 days
D)About 11 days

Question

Quizplus · Accepted Answer

The expected time is the average of the optimistic, most likely, and pessimistic times. The variance is the square of the standard deviation, which is the square root of the variance of the optimistic, most likely, and pessimistic times. The variance of the optimistic, most likely, and pessimistic times is 12, so the standard deviation is the square root of 12, which is 3.46. The expected time is the average of the optimistic, most likely, and pessimistic times, which is (3 + 6 + 18) / 3 = 9 days.

An Activity Has a Pessimistic Time That Is Four Times