Exponential distribution calculator
You can see a sample solution below. Enter your data to get the solution for your question
$$ \displaylines{---} $$
$$ \displaylines{ \lambda\; = \frac{1}{Mean\,time} = \frac{1}{0.5}
= 2.0
\\ \\ The\;question\;is\;
P(X<2)
\\ \\ Formula\;for\;Exponential\;Distribution\;is\;P(X<a)\;= 1-e^{-\lambda*a}
\\ \\ P(X<2)
=\; 1-e^{-2.0*2}
\\ \\ = \mathbf{\color{Red}{0.981684}}
} $$