What value is assigned to an event that is certain not to happen?

The value assigned to an event that is certain not to happen is 0. In probability theory, the value of an event reflects its likelihood of occurrence. An event with a probability of 0 indicates that there is no chance of that event occurring.

To further contextualize this, consider the probability scale, which ranges from 0 to 1. A value of 1 represents an event that is certain to happen, while a value of 0 represents an event that will not happen at all. Values between 0 and 1 reflect varying degrees of uncertainty, with 0.5 indicating an event that is equally likely to occur or not occur. An undefined value would imply a lack of clarity around the event's occurrence, which does not fit this situation. Thus, assigning a value of 0 to an event that is certain not to happen aligns with the fundamental principles of probability.