1. **State the problem:** You pay 5 dollars to play a game where a fair six-sided die is rolled. You receive a payout equal to the number of dots on the die face. The net gain is the payout minus 5 dollars.
2. **Formula for expected value:** The expected value $E$ of the net gain is given by
$$E = \sum (\text{net gain} \times \text{probability})$$
3. **Calculate net gains for each outcome:**
- If the die shows 1, net gain = $1 - 5 = -4$
- If the die shows 2, net gain = $2 - 5 = -3$
- If the die shows 3, net gain = $3 - 5 = -2$
- If the die shows 4, net gain = $4 - 5 = -1$
- If the die shows 5, net gain = $5 - 5 = 0$
- If the die shows 6, net gain = $6 - 5 = 1$
4. **Calculate expected value:**
Since the die is fair, each outcome has probability $\frac{1}{6}$.
$$E = \frac{1}{6}(-4) + \frac{1}{6}(-3) + \frac{1}{6}(-2) + \frac{1}{6}(-1) + \frac{1}{6}(0) + \frac{1}{6}(1)$$
5. **Simplify the sum:**
$$E = \frac{-4 - 3 - 2 - 1 + 0 + 1}{6} = \frac{-9}{6}$$
6. **Simplify fraction:**
$$E = \frac{\cancel{-9}}{\cancel{6}} = -1.5$$
7. **Interpretation:** The expected value of the game is $-1.5$, meaning on average you lose 1.5 dollars per game.
8. **Is the game fair?** A fair game has an expected value of 0. Since $E = -1.5$, the game is not fair; it favors the house.
**Final answer:** The expected payoff of the game is $-1.5$. The game is not fair.
Expected Die Payoff 3E821A
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