## Essentials of Statistics (5th Edition)

$0.9999$
We know that the sum of the probabilities is 1 and that $probability=\frac{number \ of \ good \ outcomes}{number\ of\ all\ outcomes}$. Therefore $P(A)+P(\overline{A})=1.$ Therefore $P(A)=\frac{1}{10000}=0.0001$ and therefore $P(\overline{A})=1-P(A)=1-0.0001=0.9999$