Accession Number:

ADP002309

Title:

Approximately Bounded Risk Regions,

Descriptive Note:

Corporate Author:

GRUMMAN AEROSPACE CORP BETHPAGE NY

Personal Author(s):

• Wilder,J. J.
• Black,R. L.

Report Date:

1983-07-15

Pagination or Media Count:

6.0

Abstract:

A Grass Root estimate consists of dividing a complete project into identifiable activities which taken together include all required tasks - a Work Breakdown Structure WBS. The cost to complete each activity is separately estimated, usually based on a mixture of experience and analogy with previously completed similar tasks. These WBS element estimates are then added to become a total cost estimate. Usually manhours are estimated and dollars are found by applying the rate applicable to each skill code. Also various additional factors are also included, such as indirect allocations, GA and fee. These factors add some computing complication but do not change the basic approach, so they will be ignored here. An uncertainty analysis covers the same ground. It uses the same WBS. However, the cost estimates of the individual WBS elements are expressed as probability distributions rather than point estimates. Then it adds the distributions to obtain a total probability function. This resulting function expresses the range of possible costs in terms of their probabilities of being achieved.

Descriptors:

• *Cost estimates
• *Risk
• *Method of moments
• Probability distribution functions
• Hand held
• Calculators
• Libraries
• Fortran
• Subroutines

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE