Probability Methods for Cost Uncertainty Analysis, 2nd Edition

246 Probability Methods for Cost Uncertainty Analysis

where

c

2

c

2

c

Y

I

2

1

(I) = c

1



X

121

+ c

1

I

x

122

+···+c

1

I

x

12m

Y

2

(I) = c

1



+

c

I

x

12



)

I

2

(m 1

X

+

12



(m

I

+2)



+···+

X

12(m



+k)





In Equation 6.96, Y

1

(I) could represent software functions that have indepen-

dent development efforts while Y

2

(I) could represent software functions that

have dependent development efforts. Equation 6.96 is traditionally applied

when a combination of independently developed software functions, and a

set of software functions that share functionality, characterizes the system.

Equation 6.95 (refer to Chapter 5) might be used when software cost is

based on the total size I (in DSI) of the software to be developed and its devel-

opment productivity rate P

r