Final answer:
The calculated probability that all three observers are wrong about the reality of event E is 12.5%.
Step-by-step explanation:
To calculate the probability that all three observers are wrong about the reality of event E, we need to make some assumptions. Let's assume that each observer has a 50% chance of being wrong, independent of the other observers. This means that the probability of an observer being wrong is 0.5, and the probability of an observer being right is also 0.5.
Since each observer's decision is independent of the others, we can calculate the overall probability by multiplying the probabilities together. In this case, the probability that all three observers are wrong is:
P(all three observers are wrong) = P(observer 1 is wrong) imes P(observer 2 is wrong) imes P(observer 3 is wrong) = 0.5 imes 0.5 imes 0.5 = 0.125 (12.5%)
Therefore, the calculated probability that all three observers are wrong about the reality of event E is 12.5%, which corresponds to option a.