In: Statistics and Probability
The city of Belgrade, Serbia, is contemplating building a second airport to relieve congestion at the main airport and is considering two potential sites, X and Y. Hard Rock Hotels would like to purchase land to build a hotel at the new airport. The value of land has been rising in anticipation and is expected to skyrocket once the city decides between sites X and Y. Consequently, Hard Rock would like to purchase land now. Hard Rock will sell the land if the city chooses not to locate the airport nearby. Hard Rock has four choices: (1) buy land at X, (2) buy land at Y, (3) buy land at both X and Y, or (4) do nothing. Hard Rock has collected the following data (which are in millions of euros): Site X Site Y Current purchase price 26 22 Profits if airport and hotel built at this site 50 40 Sale price if airport not built at this site 12 7 Hard Rock determines there is a 50% chance the airport will be built at X (hence, a 50% chance it will be built at Y).
Solution
We will solve this problem using EMV.
Back-up Theory
EMV (Expected Monetary Value) Criterion
Under this criterion, for each decision option, the pay-offs under various States of Nature (SON’s) are multiplied by the respective probability to obtain the EMV for that decision option. i.e.,
If there are k decision options (strategies), D1, D2, ….., Dk, r States of Nature, S1, S2, ….., Sr, then, the EMV for Di = ∑[j = 1, r]{Pij x pj}, where Pij = pay-off for Di under Sj and pj = probability of Sj.
Then, the decision option which yields the maximum EMV is selected.
Now, to work out the answer,
In the given problem,
D1: Buy land at X, D2:Buy land at Y, D2: Buy land at both X and Y, D4: Do nothing.
S1: Airport is built at site X, S2: Airport is built at site Y
Pay-off Calculations [all figures in million euros]
Airport is built at site X and land is bought at site X: i.e., D1S1 combination:
a profit of 50.
Airport is built at site X but land is bought at site Y: D1S2 combination:
land at site Y has to be sold out incurring a loss of (22 - 7) = - 15 being the difference between the purchase price and the resale price.
Airport is built at site Y and land is bought at site Y: i.e., D2S2: combination:
a profit of 40.
Airport is built at site Y but land is bought at site X: D1S2 combination:
land at site X has to be sold out incurring a loss of (26 - 12) = - 14 being the difference between the purchase price and the resale price.
Airport is built at site X and land is bought at site X and site Y:
i.e., D3S1 combination: a profit of 50 from site X less loss due to resale of land at site Y = 50 – (15) = 35.
Airport is built at site Y and land is bought at site X and site Y: D3S2 combination:
a profit of 40 from site Y less loss due to resale of land at site X = 40 – (14) = 26.
For D4, the pay-off is zero under both S1 and S2.
EMV Calculations
Di |
Pay-off |
EMV |
|
S1 |
S2 |
||
D1 |
50 |
- 14 |
18 |
D2 |
- 15 |
40 |
12.5 |
D3 |
35 |
26 |
30.5 |
D4 |
0 |
0 |
0 |
Pj |
0.5 |
0.5 |
Conclusion
Since EMV of 30.5 is maximum, the optimum decision is D3,
i.e., to buy land at both sites. ANSWER