Poisson inverse cumulative distribution function
X = poissinv(P,lambda)
X = poissinv(P,lambda) returns the smallest value X such that the Poisson cdf evaluated at X equals or exceeds P, using mean parameters in lambda. P and lambda can be vectors, matrices, or multidimensional arrays that all have the same size. A scalar input is expanded to a constant array with the same dimensions as the other input.
If the average number of defects (λ) is two, what is the 95th percentile of the number of defects?
poissinv(0.95,2) ans = 5
What is the median number of defects?
median_defects = poissinv(0.50,2) median_defects = 2