Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Probability

Question:

60% members of a committee favour a certain proposal and 40% members oppose the proposal. A member is selected and let the random variable $X = 0$ if he opposes and $X = 1$ if he is in favour. Then the variance of the random variable X is

Options:

$\frac{3}{5}$

$\frac{6}{5}$

$\frac{6}{25}$

$\frac{3}{10}$

Correct Answer:

$\frac{6}{25}$

Explanation:

The correct answer is Option (3) → $\frac{6}{25}$ **

Given probabilities:

$P(X = 1) = 0.6$, $P(X = 0) = 0.4$

Mean:

$E(X) = (1)(0.6) + (0)(0.4) = 0.6$

Variance formula for a Bernoulli random variable:

$Var(X) = p(1 - p)$

Here, $p = 0.6$

$Var(X) = 0.6(1 - 0.6) = 0.6(0.4) = 0.24$

Variance of X = 0.24