Final answer:
The expected value of a prediction with the given probabilities and outcomes is calculated by multiplying each outcome by its probability and summing the results. The calculated expected value in this scenario is $15.
Step-by-step explanation:
To find the expected value of a prediction with three possible outcomes, you multiply each outcome by its respective probability and sum the results. The formula for expected value (E[X]) is:
E[X] = (Outcome 1 × Probability 1) + (Outcome 2 × Probability 2) + (Outcome 3 × Probability 3)
In this case, the outcomes and probabilities are:
- $50 with a 20% chance (0.20)
- $25 with a 50% chance (0.50)
- -$25 with a 30% chance (0.30) - Note that this is a loss, hence the negative sign
Applying the values:
E[X] = ($50 × 0.20) + ($25 × 0.50) + (-$25 × 0.30)
E[X] = $10 + $12.50 - $7.50
E[X] = $15
Therefore, the correct answer is c. $15.