The sum of the occurrence of an event A and its non-occurrence Ᾱ is equal to
1
0
Not defined
2
P(A) + P(Ᾱ) = 1
If the probability of occurrence of an event is 0.9, then what is the probability of its non-occurrence?
If the occurrence of an event precludes the occurrence of a second event, and vice versa, then the events are