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JEE Mains · Maths · STD 11 - 13. statistics

Let \(\mathrm{X}\) be a random variable with distribution.
\(\mathrm{x}\) \(-2\) \(-1\) \(3\) \(4\) \(6\)
\(\mathrm{P}(\mathrm{X}=\mathrm{x})\) \(\frac{1}{5}\) \(\mathrm{a}\) \(\frac{1}{3}\) \(\frac{1}{5}\) \(\mathrm{~b}\)
If the mean of \(X\) is \(2.3\) and variance of \(X\) is \(\sigma^{2}\), then \(100 \sigma^{2}\) is equal to :

  1. A \(781\)
  2. B \(100\)
  3. C \(529\)
  4. D \(1310\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(781\)

Step-by-step Solution

Detailed explanation

\(\mathrm{x}\) \(-2\) \(-1\) \(3\) \(4\) \(6\) \(\mathrm{P}(\mathrm{X}=\mathrm{x})\) \(\frac{1}{5}\) \(\mathrm{a}\) \(\frac{1}{3}\) \(\frac{1}{5}\) \(\mathrm{~b}\) \(\bar{X}=2.3\) \(-a+6 b=\frac{9}{10} \ldots (1)\) \(\sum P_{i}=\frac{1}{5}+a+\frac{1}{3}+\frac{1}{5}+b=1\)…