Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Probability Distributions

Question:

The probability distribution of a random discrete variable is given

X

-1

0

1

2

3

P(X)

  0.1  

  p  

  0.3  

  q  

  r  

If it is known that P(X=1) is the mean of P(X=0) and P(X=2).

Then the value of $r$ is:

Options:

0

0.1

0.2

0.3

Correct Answer:

0

Explanation:

The correct answer is Option (1) → 0 **

Given probabilities:

$P(X=-1)=0.1,\; P(X=0)=p,\; P(X=1)=0.3,\; P(X=2)=q,\; P(X=3)=r$

The given condition:

$P(X=1)$ is the mean of $P(X=0)$ and $P(X=2)$

This means:

$0.3=\frac{p+q}{2}$

So:

$p+q=0.6$

Using total probability = 1:

$0.1 + p + 0.3 + q + r = 1$

$p + q + r = 0.6$

Since $p+q=0.6$:

$0.6 + r = 0.6$

$r = 0$

Final values:

$p + q = 0.6$ (infinitely many pairs possible)

$r = 0$