Answer 1

Let X denote the number of defects on a plywood sheet.
Given, m = 1, e^–1 = 0.3678
∴ X ~ P(m) ≅ X ~ P(1)
The p.m.f. of X is given by

P(X = x) = `("e"^-"m" "m"^x)/(x!)`

∴ P(X = x) = `("e"^-1 (1)^x)/(x!)`

P (at least one defect)
= P (X ≥ 1)
= 1 – P (X = 0)
= 1 – 0.3678
= 0.6322