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Probability — MATHS STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceMATHSProbability1 Mark
Question
In a binomial distribution, the probability of getting success is $\frac{1}{4}$ and standard deviation is 3. Then, its mean is:
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Answer

  1. 12
Solution:
$\text{p}=\frac{1}{4},\sqrt{\text{npq}}=3$
$\Rightarrow\text{q}=\frac{3}{4},\text{npq}=9$
$\Rightarrow\text{Mean = np}=\frac{9}{\text{q}}$
$\Rightarrow\text{Mean}=9\times\frac{4}{3}=12$

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