Probability Methods for Cost Uncertainty Analysis, 2nd Edition

Confidence

Level

1

0.59

α = 0.34

x

0

Cost Growth Factor (CGF)

Lognormal (0.192959, (0.478593)

2

)

CV = 0.51 = –––– = –– α = 0.34

0.69

1.36

σ

µ

1

1.36

413 Enhanced Scenario-Based Method

TABLE 12.7

NCCA Study: MS B Historical Cost Growth Factors and CVs

Without Quantity Adjustment Quantity-Adjusted

Statistics Base-Year $ Then-Year $ Base-Year $ Then-Year $

Mean 1.48 1.84 1.23 1.36

Standard Deviation 0.94 1.60 0.44 0.69

CV 0.63 0.87 0.36 0.51

In Figure 12.10, this is shown by x = 1. From Figure 12.10, and the data in

the last column of Table 12.7, it can be shown that x = 1 falls at the 34th per-

centile condence