a CASH FLOWS ARE EXPRESSED AS COSTS (I.E., POSITIVE VALUES REPRESENT COST NOT REVENUE)
ALTERNATIVE A WILL BE PREFERRED IF PW(COSTS A) < PW(COSTS B) OR IF PW(COSTS A-B) < 0
VARIANCE = (STANDARD DEVIATION)^2
SALVAGE VALUE IS TREATED AS A NEGATIVE CASH FLOWS SINCE CASH FLOWS ARE EXPRESSED
EXPECTED VALUE OF A DIFFERENCE IS THE DIFFERENCE OF THE EXPECTED VALUES.
VARIANCE OF A DIFFERENCE IS THE SUM OF VARIANCES.
EXPECTED PW IS THE DISCOUNTED SUM OF EXPECTED CASH FLOWS
VARIANCE OF PW IS THE SUM OF THE VARIANCES OF CASH FLOWS TIMES
THE DISCOUNT FACTORS SQUARED,
EOY E[CF A] VAR[CF A] E[CF B] VAR[CF B] E[A-B] VAR[A-B] (P|F i%,n) E[PW A-B] VAR[PW A-B]
0 $13,000 0 $0 0 $13,000 0 1.00000 $13,000 0
1 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.86957 -$2,174 614,367
2 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.75614 -$1,890 464,550
3 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.65752 -$1,644 351,266
4 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.57175 -$1,429 265,608
5 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.49718 -$1,243 200,838
6 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.43233 -$1,081 151,862
7 $5,000 250,000 $7,500 562,500 -$2,500 812,500 0.37594 -$940 114,830
8 $3,000 890,000 $7,500 562,500 -$4,500 1,452,500 0.32690 -$1,471 155,221
EXCEL’S NORMSDIST FUNCTION IS USED TO DETERMINE THE PROBABILITY OF
THE PW EXCEED A VALUE OF INTEREST.
PROB(PW OF A-B<VALUE) = 1 – NORMSDIST((E(PW A-B) – VALUE) / SD(PW A-B))
PROB(PW OF A-B<0) = 1 – NORMSDIST((1,128 – 0) / 1522.68)
THE PROBABILITY THAT A IS THE PREFERRED ALTERNATIVE IS 0.229 OR 22.9%
add’l info THE FOLLOWING TABLE SHOWS THE DATA AND FUNCTIONS NECESSARY
TO RUN THE @RISK SIMULATION
SIMULATION PARAMETERS: 10,000 ITERATIONS, LATIN HYPERCUBE, SEED=987654321
THE PROBABILITY THAT A IS THE PREFERRED ALTERNATIVE IS 0.234 OR 23.4%
b THE FOLLOWING TABLE SHOWS THE DATA AND FUNCTIONS NECESSARY
TO RUN THE @RISK SIMULATION
SIMULATION PARAMETERS: 10,000 ITERATIONS, MONTE CARLO, SEED=987654321
=RiskNormal(5000,500)-RiskNormal(2000,800)
=RiskOutput(“PW(COST A-B)”)+NPV(0.15,EOY1:EOY8)+EOY0