Suppose 1 % of a certain brand of Christmas lights is defective. Use the Poisson approximation to compute the probability that in a box of 25 there will be at most one defective bulb.

Let X be the number of defectives in 25 lights
The rate of 1 defectives in 100 lights is same as 1/100 ∗ 25 = 0.25 in 25 lights
X follows Poisson distribution with parameter (rate) λ = 0.25
X ∼ Poisson (λ = 0.25)
P (X ≤ 1),λ = 0.25
P (X ≤ 1) = P (0 ≤ X ≤ 1) =P (X = 0) + P (X = 1)
P (X = 0) =...