Investment Preference
1. **Problem Statement:**
We have three investment alternatives with payoffs under three economic conditions and their probabilities. We want to find the preferred decision using expected value and expected utility approaches.
2. **Expected Value Approach:**
The expected value (EV) for each investment is calculated as:
$$EV = \sum (\text{payoff} \times \text{probability})$$
Calculate EV for each investment:
- Investment A: $$EV_A = 100 \times 0.40 + 25 \times 0.30 + 0 \times 0.30 = 40 + 7.5 + 0 = 47.5$$
- Investment B: $$EV_B = 75 \times 0.40 + 50 \times 0.30 + 25 \times 0.30 = 30 + 15 + 7.5 = 52.5$$
- Investment C: $$EV_C = 50 \times 0.40 + 50 \times 0.30 + 50 \times 0.30 = 20 + 15 + 15 = 50$$
**Preferred decision by expected value:** Investment B with EV = 52.5
3. **Expected Utility Approach:**
Given lotteries with payoff $100,000 with probability $p$ and $0$ with probability $(1-p)$, decision makers express indifference probabilities for certain profits. We use these to find utility values.
Utility for $100,000 is normalized to 1 and for $0$ is 0.
For each decision maker, utility of profit $x$ is equal to the indifference probability $p$:
- Decision Maker A utilities:
- $75,000: U(75,000) = 0.80$
- $50,000: U(50,000) = 0.60$
- $25,000: U(25,000) = 0.30$
- Decision Maker B utilities:
- $75,000: U(75,000) = 0.60$
- $50,000: U(50,000) = 0.30$
- $25,000: U(25,000) = 0.15$
Calculate expected utility (EU) for each investment:
For Decision Maker A:
$$EU_A = 0.40 \times 1 + 0.30 \times 0.30 + 0.30 \times 0 = 0.40 + 0.09 + 0 = 0.49$$
$$EU_B = 0.40 \times 0.80 + 0.30 \times 0.60 + 0.30 \times 0.30 = 0.32 + 0.18 + 0.09 = 0.59$$
$$EU_C = 0.40 \times 0.60 + 0.30 \times 0.60 + 0.30 \times 0.60 = 0.24 + 0.18 + 0.18 = 0.60$$
For Decision Maker B:
$$EU_A = 0.40 \times 1 + 0.30 \times 0.15 + 0.30 \times 0 = 0.40 + 0.045 + 0 = 0.445$$
$$EU_B = 0.40 \times 0.60 + 0.30 \times 0.30 + 0.30 \times 0.15 = 0.24 + 0.09 + 0.045 = 0.375$$
$$EU_C = 0.40 \times 0.30 + 0.30 \times 0.30 + 0.30 \times 0.30 = 0.12 + 0.09 + 0.09 = 0.30$$
**Preferred decisions by expected utility:**
- Decision Maker A prefers Investment C (EU=0.60)
- Decision Maker B prefers Investment A (EU=0.445)
4. **Explanation for different preferences:**
Decision Makers A and B have different risk preferences reflected in their utility functions. Decision Maker A values moderate payoffs more (higher utilities for lower profits), showing risk aversion, while Decision Maker B values high payoffs more selectively, showing different risk tolerance. This leads to different preferred investments under expected utility despite the same payoffs.