The time between arrivals at an ATM machine follows an exponential distribution with $\theta = 10$ minutes. Find the probability that less than 25 minutes will pass between arrivals.
A) 0.082085
B) 0.670320
C) 0.917915
D) 0.329680

Question

Quizplus · Accepted Answer

The exponential distribution with parameter $\theta = 10$ has a cumulative distribution function $F(x) = 1 - e^{-x/\theta}$. For $x = 25$, $F(25) = 1 - e^{-25/10} = 1 - e^{-2.5} \approx 0.917915$.

The Time Between Arrivals at an ATM Machine Follows an Exponential