Question

Approximately 4% of silicon wafers produced by a manufacturer have fewer than two large flaws. If Y, the number of flaws per wafer , has a Poisson distribution, what proportion of wafer have more than five large flaws?

Answer 1

Y ~ Po (λ)
P(Y < 2) = P(Y ≤ 1) = 0.04
Plug into the pdf for Po(λ), and solve for λ

Answer 2

After that, use your answer to find P(Y > 5)