<Dl> <Dd> p = 1 100 = 0.01 (\ displaystyle p = (1 \ over 100) = 0.01). </Dd> </Dl> <Dd> p = 1 100 = 0.01 (\ displaystyle p = (1 \ over 100) = 0.01). </Dd> <P> So the probability that such an event occurs exactly once in 10 successive years is: </P> <Dl> <Dd> P (X = 1) = (10 1) × 0.01 1 × 0.99 9 (\ displaystyle P (X = 1) = (\ binom (10) (1)) \ times 0.01 ^ (1) \ times 0.99 ^ (9)) <Dl> <Dd> ≈ 10 × 0.01 × 0.914 (\ displaystyle \ approx 10 \ times 0.01 \ times 0.914) </Dd> <Dd> ≈ 0.0914 (\ displaystyle \ approx 0.0914 \,) </Dd> </Dl> </Dd> </Dl>

The value of x which is exceeded 50 of the time in the duration of measurement is