Mathematics for IGCSE & O level - Probability (Section 2 - No. 20)
Which of the following are true about a probability distribution?
The sum of the probabilities of all possible outcomes must equal 1.
Each probability value must be between 0 and 1, inclusive.
The probabilities can be negative.
It describes the likelihood of different outcomes.
Explication
The sum of probabilities is always one. Probabilities can never be negative and only lie between 0 and 1.