Question

Let X ~ B(n, p). If n = 10 and E(X) = 5, using the following activity find p and Var(X)

Solution: E(X) = `square = 5 square "p" = square, "q" = square`

Var(X) = `square`

Answer 1

E(X) = np= 5

∴ 10p = 5

p = `1/2`, q = `1/2`

Var(X) = npq

= `10 xx 1/2xx 1/2`

= 25