In: Statistics and Probability
3. Suppose you are thinking of investing $100,000 in stock indexes. You are currently considering investing either in the financial sector or the technolgy sector but the returns will depend on the state of the economy. The following table summarizes the estimated net profts that would be realized during the next two years for each of the two investment alternatives you are considering.
State of the Economy |
|||
Good Economy |
Poor Economy |
||
Healthcare |
$60,000 |
$-10,000 |
|
Decision Alternative |
Technology |
$90,000 |
$-50,000 |
Probability |
0.45 |
0.55 |
(a) We draw a decision tree and calculate expected values for each investing decision.
From the above, it is clear that the decision to invest in Healthcare sector (also called financial sector in the question) will maximize the expected profit.
(b) Let us first calculate the expected value with perfect forecast from the above decision map,
If it is known that the state of the economy will be good, then the best decision alternative would be to invest in the Technology sector as it will provide a profit of $90000.
If it is known that the state of the economy will be bad, then the best decision alternative would be to invest in the Healthcare sector as it will help minimize the loss. We can say that the profit will be -$10000.
Thus, expected value of the decision strategy with perfect forecast (EVPF) = 0.45*90000+0.55*(-10000)
= $35000
From part(a), we get the expected value of the decision strategy without perfect forecast (EVWOPF) = $21500
Subtracting the two above, we get the Expected value of perfect forecast = EVPF-EVWOPF
= 35000 - 21500
=$13500
Thus, the maximum amount you should be willing to pay for a perfect forecast of the state of the economy is $13500.
(c) This is the case of decision tree with sample information. The decision tree is shown below:
In the above diagram, we have made the assumption that the analyst predicts the good or bad economic scenario with equal probability 0.5 in the absence of any given information.
Calculating expected values at different nodes,
EV (Node4) = Max [EV(Node6), EV(Node7)] =Max [0.92*60000-0.08*10000, 0.92*90000-0.08*50000)] =Max[54400,78800] = $78800
EV (Node5) = Max [EV(Node8), EV(Node9)] =Max [0.20*60000-0.80*10000, 0.20*90000-0.80*50000)] =Max[20000,58000] = $58000
EV (Node3) = $21500 {calculated in part(a) of the question}
EV (Node2) = 0.5*EV (Node4) + 0.5*EV (Node5) = $136800
EVSI = 136800-21500 = $115300
EVSI shows that hiring the financial analyst for prediction adds $1,15,300 to the expected value of net profit over the alternative of investing without the sample information provided by the analyst.
Hence, we will hire the analyst.