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Question: Answered & Verified by Expert
If the mean and variance of a binomial variable $\mathrm{X}$ are 2.4 and 1.44 respectively, then the parameters $n$ and $p$ are respectively
MathematicsProbabilityAP EAMCETAP EAMCET 2023 (17 May Shift 1)
Options:
  • A $6, \frac{2}{5}$
  • B $4, \frac{3}{5}$
  • C $6, \frac{3}{5}$
  • D $8, \frac{1}{3}$
Solution:
1742 Upvotes Verified Answer
The correct answer is: $6, \frac{2}{5}$
$\begin{aligned} & \text {} \because \text { Mean }=2.4 \Rightarrow n p=2.4 \\ & \text { Variance }=1.44 \Rightarrow n p(1-p)=1.44 \\ & \Rightarrow 2.4(1-p)=1.44 \Rightarrow p=\frac{2}{5} \\ & \text { and } n p=2.4 \Rightarrow n=2.4 \times \frac{5}{2}=6.0\end{aligned}$

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