5.2. Some Rules of Probability

Several basic rules govern the theory of probability.

Rule 1: A probability is a number between 0 and 1 that is assigned to an event or outcome of some process or experiment.

The smallest possible probability value is 0. An event or outcome that has a probability of 0 is called a null event and has no chance of occurring. In the case of the die, the event of a face of seven has a probability of 0 because such an event cannot occur. In addition, no event can possibly have a probability that is below 0.

The largest possible probability value is 1.0. An event or outcome that has a probability of 1.0 is called a certain event and must occur. When rolling a single die, the event of a face with fewer than seven dots has ...

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