Civil Engineering - UPSC Civil Service Exam Questions - Discussion
Discussion Forum : UPSC Civil Service Exam Questions - Section 1 (Q.No. 30)
30.
In a PERT network, the activity durations are given as to (optimistic), tp (pessimistic) and tm (most likely time). What is the variance of is activity ?
None of the above
Discussion:
14 comments Page 2 of 2.
Ashok Sharma said:
10 years ago
A is expected time.
B is standard deviation.
C is variance.
B is standard deviation.
C is variance.
Rakesh said:
1 decade ago
"B" is standard deviation.
"C" is variance.
"C" is variance.
Engr Shbabir said:
1 decade ago
Optimistic time (O) : the minimum possible time required to accomplish a task, assuming everything proceeds better than is normally expected.
Pessimistic time (P) : the maximum possible time required to accomplish a task, assuming everything goes wrong (but excluding major catastrophes).
Most likely time (M) : the best estimate of the time required to accomplish a task, assuming everything proceeds as normal.
Expected time (TE) : the best estimate of the time required to accomplish a task, accounting for the fact that things don't always proceed as normal (the implication being that the expected time is the average time the task would require if the task were repeated on a number of occasions over an extended period of time).
So Option A is right.
Pessimistic time (P) : the maximum possible time required to accomplish a task, assuming everything goes wrong (but excluding major catastrophes).
Most likely time (M) : the best estimate of the time required to accomplish a task, assuming everything proceeds as normal.
Expected time (TE) : the best estimate of the time required to accomplish a task, accounting for the fact that things don't always proceed as normal (the implication being that the expected time is the average time the task would require if the task were repeated on a number of occasions over an extended period of time).
So Option A is right.
Lloyd P said:
1 decade ago
Letter (B) corresponds to Standard Deviation of an Activity.
Squaring such will yield to Variance of an Activity, in this regard the answer should be Letter (C).
Squaring such will yield to Variance of an Activity, in this regard the answer should be Letter (C).
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