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AP EAMCET · Maths · Probability

If the mean and variance of a binomial variable \(\mathrm{X}\) are 2 and 1 respectively, then \(\mathrm{P}(\mathrm{X}>1)=\)

  1. A \(\frac{11}{32}\)
  2. B \(\frac{1}{8}\)
  3. C \(\frac{11}{12}\)
  4. D \(\frac{11}{16}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\frac{11}{16}\)

Step-by-step Solution

Detailed explanation

\(\because\) Mean \(=2 \Rightarrow n p=2\) \(\begin{aligned} & \text { and Variance }=1 \Rightarrow n p q=1 \\ & \Rightarrow 2(1-P)=1 \Rightarrow 2-2 p=1 \\ & \Rightarrow p=1 / 2\end{aligned}\) \(\therefore \frac{1}{2} n=2 \Rightarrow n=4\)…