Sample Response: Probability is the ratio of the desired outcomes to all possible outcomes. If there are no desired outcomes, the ratio is 0 over all possible outcomes, thus 0. If the event is all possible outcomes, the ratio is all possible outcomes over all possible outcomes, thus 1. Which of the following did you use in your response? Check all that apply. Probability is desired outcomes over all possible outcomes. No desired outcomes would be 0 over all possible outcomes. If the desired outcome is all possible outcomes, the ratio is 1.