The expected value for the estimation variable (size), S, can be computed as a weighted average of the optimistic(Sopt), most likely (Sm), and pessimistic (Spess) estimates given as
(a) EV = (Sopt + 4Sm + Spess)/4
(b) EV = (Sopt + 4Sm + Spess)/6
(c) EV = (Sopt + 2Sm + Spess)/6
(d) EV = (Sopt + 2Sm + Spess)/4
The question was asked by my school teacher while I was bunking the class.
My enquiry is from Decomposition Techniques in Software Project Planning in chapter Software Management of Software Engineering