Question

Let the probability mass function (p.m.f.) of a random variable X be P(X = x) = `""^4C_x (5/9)^x xx (4/9)^(4 - x)`, for x = 0, 1, 2, 3, 4 then E(X) is equal to ______.

Options

• `20/9`

• `9/20`

• `12/9`

• `9/25`

Answer 1

Let the probability mass function (p.m.f.) of a random variable X be P(X = x) = `""^4C_x (5/9)^x xx (4/9)^(4 - x)`, for x = 0, 1, 2, 3, 4 then E(X) is equal to `underlinebb(20/9)`.

Explanation:

P (X = x) is binomial distribution with n = 4, p = `5/9` and q = `4/9`

E(X) = np

= `4 xx (5/9)`

= `20/9`