Which statement describes a basic property of probabilities?

The chosen statement accurately reflects a fundamental characteristic of probabilities: the probability of any event, denoted as P(A), must be greater than or equal to zero. This property is rooted in the definition of probability, which indicates that it measures the likelihood of an event occurring, existing on a scale from 0 to 1. A probability of 0 means that the event cannot occur at all, while a probability of 1 indicates certainty that the event will happen. Therefore, stating that P(A) cannot be less than 0 aligns perfectly with these foundational principles of probability theory.

In contrast, the other statements either misrepresent the principles of probability or provide incorrect information. For instance, the idea that P(A) can exceed 1 does not hold true, as probabilities are confined to the range from 0 to 1. As for asserting that P(A) is always equal to 0.5, this is misleading because probabilities can take on any value within the defined range based on the specific event in question. Lastly, saying that P(A) is not defined for all events is incorrect because probabilities are applicable to defined events within the context of the sample space. The definition of probability is broad enough to encompass all possible events in that space