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Disjoint
Two sets are called disjoint if they have no elements in common,
that is, if their intersection (the set of all the elements they have
in common) is empty. Two disjoint events are also called
mutually exclusive events. For example, if you sample patients
randomly from a clinic, then the event that the patient was male is
disjoint from the event that the patient had a diagnosis of cervical
cancer. Knowing that the patient had cervical cancer rules out the
possibility that the person was a male, and vice versa.
Knowing that one of two disjoint events occurred provides information
about the occurrence of the other - namely that the other did not occur.
