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AP EAMCET · Maths · Probability

The probability distribution of a random variable X is given below
X123456
\(\mathrm{P}\left(\mathrm{X}=\mathrm{x}_{\mathrm{i}}\right)\)\(\alpha\)\(\alpha\)\(\alpha\)\(\beta\)\(\beta\)0.3

If \(\mu\) and \(\sigma^2\) represent the mean and variance of X and \(\mu=4.2\), then \(\sigma^2+\mu^2=\)

  1. A 20.4
  2. B 10.8
  3. C 16.4
  4. D 21.4
Verified Solution

Answer & Solution

Correct Answer

(A) 20.4

Step-by-step Solution

Detailed explanation

\(3\alpha + 2\beta + 0.3 = 1 \implies 3\alpha + 2\beta = 0.7\) \(1\alpha + 2\alpha + 3\alpha + 4\beta + 5\beta + 6(0.3) = 4.2 \implies 6\alpha + 9\beta + 1.8 = 4.2 \implies 6\alpha + 9\beta = 2.4 \implies 2\alpha + 3\beta = 0.8\) \(\alpha = 0.1, \beta = 0.2\)…