Question

The mean number of errors due to a bug occurring in a minute is 0.0001. What is the
probability that no error will occur in 20 minutes?

Answer 1

$\lambda\; per\; 20\; minute =20\times 0.0001=0.0020\\ P(X=0)=\frac{e^{-0.0020}(0.0020)^{0}}{0!}\approx0.998$