Cars arrive at a toll both according to a Poisson process with mean 80 cars per hour. If the attendant makes a one-minute phone call, what is the probability that at least 1 car arrives during the call?
If the average is 80 per hour, then the average is also (80)/(60)=(4)/(3) per minute: lambda = (4)/(3) Fromula geometric probability: P(X=k)=(lambda^(k)e^(-lambda))/(k!) Determine the probability: P(X=0)=((4/3)^(0)e^(-4/3))/(0!)=0.2636 Use the complement rule P(X>= 1)=1-P(X=0)=1-0.2636=0.7364 Result: 0.7364