The number of errors in a textbook follows a Poisson distribution with a mean of 0.01 errors per page. What is the probability that there are three or less errors in 100 pages?

Let X be the number of errors in 100 pages
The rate of 0.01 errors in 1 pages is same as 0.01/1 ∗ 100 = 1 in 100 pages
X follows Poisson distribution with parameter (rate) λ = 1
X ∼ Poisson (λ = 1)
P (X ≤ 3),λ = 1
P (X ≤ 3) = P (0 ≤ X ≤ 3) =P (X = 0) + P (X = 1) + P (X = 2) + P (X = 3)
P (X =...