Event
Impossible: The probability of an event is 0.
Certain: The probability of an event is 1.
Unusual event: An event that is unlikely to occur because of low probability.
If an event is impossible, the probability of the event is 0. If an event is certain, the probability of the event is 1.
The closer a probability is to 1, the more likely the event will occur. For example, an event that has a probability of .375 is more likely to occur than an event that has a probability of .125.
The closer a probability is to 0, the less likely the event will occur. This type of event is defined as an unusual event. Typically, a probability of 5%, or .05, is considered unusual.
