# What are the mean and standard deviation of a binomial probability distribution with n=21  and p=4/17 ?

Mean $= \frac{84}{17} = 4.94118$
Standard deviation $= 1.94385$

#### Explanation:

For Binomial Probability Distribution

The Mean $= n p = 21 \left(\frac{4}{17}\right) = \frac{84}{17}$
Standard Deviation $= \sqrt{n p q} = \sqrt{n p \left(1 - p\right)} = \sqrt{21 \left(\frac{4}{17}\right) \left(1 - \frac{4}{17}\right)} = 1.94385$

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