Multiple Choice Question Which one of the following is true about events that are both mutually exclusive and collectively exhaustive? The sum of their probabilities must be between 0 and 1. The sum of their probabilities must be a The sum of their probabilities must be greater than 1. The sum of their probabilities must be 1.

The correct answer is: The sum of their probabilities must be 1.<br /><br />Explanation: Events that are both mutually exclusive and collectively exhaustive are events that cannot occur at the same time (mutually exclusive) and cover all possible outcomes (collectively exhaustive). In such a case, the sum of their probabilities must be 1, as they represent all possible outcomes of the experiment.