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Question
In a binomial distribution, the probability of getting success is 1/4 and standard deviation is 3. Then, its mean is
Options
6
8
12
10
Solution
12
\[p = \frac{1}{4}\]
\[ \therefore q = 1 - \frac{1}{4} = \frac{3}{4}\]
\[\text{ Standard deviation }= 3 \]
\[ \Rightarrow\text{ Variance } = 3^2 = 9\]
\[\text{ Or npq } = 9\]
\[ \Rightarrow np = \frac{9}{q}\]
\[ = \frac{36}{3}\]
\[ = 12\]
\[\text{ Therefore, the mean of the given binomial distribution is 12 } .\]
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