Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Probability Distributions

Question:

A random variable X has the Probability Distribution :

X 1 2 3 4
P(X) $2k^2$ $k$ $k$ $k^2$

The value of k is :

Options:

$\frac{1}{3}$

$\frac{1}{5}$

$\frac{1}{2}$

$\frac{1}{6}$

Correct Answer:

$\frac{1}{3}$

Explanation:

The correct answer is Option (1) → $\frac{1}{3}$

The sum of all probabilities must be 1.

$⇒2k^2+k+k+k^2=1$

$⇒3k^2+2k-1=0$

$⇒(k+1)(k-\frac{1}{3})-1=0$

$⇒k=\frac{1}{3}$ (Probability is always positive)