When you are determining the probability of an event, why must the probability be between 0 and 1? Explain your answer.

Answer:

Probability is calculated as the ratio of the number of desired outcomes to the total number of possible outcomes. Since you cannot have fewer than zero desired outcomes and you cannot have more desired outcomes than there are total outcomes possible, the ratio must be between 0 and 1. A probability of 0 means the event is impossible, and a probability of 1 means the event is certain.