Let A be the event [tex] A=\{choosing \;an \;odd \;number\} [/tex] and B be the vent [tex] B=\{choosing \;an \;even \;number\} [/tex]. Since the intersection of the events [tex] A\cap B=\phi [/tex], the events A and B are mutually exclusive.
The number is either odd or even. Since [tex] P(A)+P(B)=1 [/tex], the events are mutually exclusive and exhaustive.
Correct choice is "the number is either odd or even".
