CUET · MATHS · PYQ PAPER 2025
The random variable X has the following probability distribution
| X | 0 | 1 | 2 | 3 |
| P(X) | a | a | b | b |
- A \(\frac{1}{8}\)
- B \(\frac{1}{4}\)
- C \(\frac{1}{2}\)
- D \(\frac{3}{8}\)
Answer & Solution
Correct Answer
(A) \(\frac{1}{8}\)
Step-by-step Solution
Detailed explanation
\(\sum P(X) = 1 \implies 2a + 2b = 1\) \(E(X) = 0a + 1a + 2b + 3b = a + 5b\) \(E(X^2) = 0^2a + 1^2a + 2^2b + 3^2b = a + 13b\) \(E(X^2) = 2E(X) \implies a + 13b = 2(a + 5b)\) \(a + 13b = 2a + 10b \implies 3b = a\) \(2(3b) + 2b = 1 \implies 8b = 1 \implies b = \frac{1}{8}\)
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