Question

Events E and F are such that P(not E or not F) = 0.25, State whether E and F are mutually exclusive.

Answer 1

P(not E or not F) = P(E ∩ F)

= P[(E ∪ F)’]

i.e. = 1 – P(E ∪ F) = 0.25

or P(E ∪ F) = 1 – 0.25

= 0.75

∴ P(E ∪ F) ≠ 0 Hence, E and F are not mutually exclusive.