Consider the number of people that show up at a bus station is Poisson with mean 2.5/h. What is the probability that at most three people show up in a four hour period?

Consider the number of people that show up at a bus station is Poisson with mean 2.5/h. What is the probability that at most three people show up in a four hour period?

X\~Poisson(λ=2.5×t)X\~Poisson(λ=2.5×t)
R code:

ppois(3,lambda=2.5*4)

## [1] 0.01033605