The complement of A is 'not A'. Their probabilities sum to 1.
Rule
P(not A) = 1 − P(A)
Sometimes 'not A' is easier than A. P(at least one heads in 5 flips) = 1 − P(no heads) = 1 − (1/2)⁵ = 31/32.
The complement of A is 'not A'. Their probabilities sum to 1.
Sometimes 'not A' is easier than A. P(at least one heads in 5 flips) = 1 − P(no heads) = 1 − (1/2)⁵ = 31/32.