by gamparano » Thu Aug 02, 2012 9:57 am
My question is in regards to applying these equations (Eqs 4-28 & 4-29, or A-4 & A-5) to determine Nexpected crashes for the example problem on page 4-62.
In applying Equations 4-28 and 4-29 EB analysis from Part B for 3 years of data, I obtain the following results:
Year Nexpected(Total) Nexpected(FI) Nexpected(PDO)
1 9.8 6.7 3.1
2 10.0 6.8 3.2
3 10.8 7.4 3.4
In applying Equations A-4 and A-5 EB analyiss from Part C to the same data, I obtain the following results:
Year Nexpected(Total) Nexpected(FI) Nexpected(PDO)
1 8.0 6.7 1.3
2 9.6 6.7 2.9
3 13.0 7.5 5.5
The average values from both methods are the same Nexpected(Total) = 10.2, Nexpected(F&I)= 7.0, and Nexpected(PDO)= 3.2, but why is there such a big difference between the annual values (i.e., year 3)? I understand that these are just predictions but are the differences acceptable and/or is the critical concern the average of the three years rather than the annual results? I would be glad to share the full spreadsheet with you.